CHAPTER XVII.

_PRIVATE LIFE._

REMINISCENCES OF MR. BRUNEL’S PRIVATE LIFE--REMOVAL TO 18 DUKE STREET, WESTMINSTER--HIS MARRIAGE, 1836--SPECIAL CONSTABLE IN 1848--MR. BRUNEL’S LOVE OF ART--HIS JOURNEY TO ITALY, 1842--ACCIDENT WITH THE HALF-SOVEREIGN, 1843--PURCHASE OF PROPERTY IN DEVONSHIRE, 1847--HIS LIFE AT WATCOMBE--THE LAUNCH OF THE ‘GREAT EASTERN,’ 1857--MR. BRUNEL’S FAILING HEALTH--JOURNEYS TO SWITZERLAND AND EGYPT, 1858--LETTER FROM PHILÆ (FEBRUARY 12, 1859)--HIS LAST ILLNESS--HIS DEATH (SEPTEMBER 15, 1859)--FUNERAL--ADDRESS OF JOSEPH LOCKE, ESQ., M.P., AT THE INSTITUTION OF CIVIL ENGINEERS (NOVEMBER 8, 1859).

Under any circumstances, and by whomsoever made, the attempt to describe Mr. Brunel’s home life must fail to satisfy those who knew him, and who remember him in the midst of his family or among his friends.

But those who did not know him, except as a professional man, or who are only acquainted with his works, will expect to find in these pages some account of his private life, and of the manner in which he spent those brief intervals of relaxation which he permitted himself to enjoy.

* * * * *

Although Mr. Brunel was never an idle man, he was able, until he obtained business on his own account, to enjoy many amusements from which in after life he was completely debarred.

This arose partly from his work under his father being near his own home and his friends, and partly from the power he possessed, and which never deserted him, of being able to throw aside cares and anxieties and to join with the utmost zest in passing amusements.

The following letter, relating to this time, is written by one who was Mr. Brunel’s constant companion during the period to which it refers:--

June 28, 1870.

‘Dear Isambard Brunel,--I will endeavour to supply you with some reminiscences of your father, before he became a public man, and was engrossed by the very severe labour of his profession.

‘The most striking feature in his character as a young man, and one which afterwards produced such great results, was an entire abnegation of self in his intercourse with his friends and associates.

‘His influence among them was unbounded, but never sought by him; it was the result of his love of fair play, of his uniform kindness and willingness to assist them, of the confidence he inspired in his judgment, and of the simplicity and high-mindedness of his character.

‘From 1824 to 1832 he joined his friends in every manly sport; and when, after his accident at the Tunnel, he was obliged to withdraw from more violent exercise, he was still ready to co-operate in the arrangements required to give effect to whatever was in hand.

‘Whether in boating, in pic-nic parties, or in private theatricals, he was always the life and soul of the party; for his skilful arrangements, as well as his never-failing invention and power of adaptation of whatever came to hand, made him the invariable leader in every amusement or sport in which he took part.

‘To ensure the success of his friends in a rowing match against time, from London to Oxford and back, in 1828, he designed and superintended the building of a four-oared boat, which, in length and in the proportion of its length to its breadth, far exceeded any boat of the kind which had then been seen on the Thames.

‘During that portion of the period to which these notes refer, when your father was engaged at the Tunnel works, the freshness and energy with which he joined in the amusements of his friends after many consecutive days and nights spent in the Tunnel--for frequently he did not go to bed, I might almost say, for weeks together--surprised them all.

‘His power of doing without sleep for long intervals was most remarkable. He also possessed the power, which I have never seen equalled in any other man, of maintaining a calm and even temper, never showing irritation even when he was bearing an amount of mental and bodily fatigue which few could have sustained. His presence of mind and courage never failed him, and it was especially exhibited after the first irruption of water into the Tunnel, when he descended in the diving-bell to examine the extent of the disturbance of the bed of the river, and the injury, if any, which had been done to the brickwork.

‘The bell could not be lowered deep enough, and he dropped himself out of the bell, holding on by a rope, and ascertained by careful examination that the brickwork was uninjured.

‘He was several minutes in the water; and upon this fact being stated, many persons, and I think the officers of the Royal Humane Society, denied the possibility of his retaining his consciousness so long in the water, forgetting, which he did not, that his lungs were filled with air at two and a half atmospheres’ pressure.

‘In 1830, he joined the Surrey Yeomanry and attended drill, and was out with the troop to which he belonged on several occasions.

‘In this capacity he was as popular as in every other; but his remarkable talent in obtaining personal influence, even among those with whom he was comparatively a stranger, was about this time most usefully exhibited during the election of his brother-in-law as member for Lambeth.

‘He made friends and conciliated opponents among all classes of electors--especially among working men, large bodies of whom he met on several occasions--and among all shades of politicians; and to his energy, good judgment and skilful arrangement of electioneering details, which were not then so well understood as they now are, very much of the success achieved was due.

‘No one, I believe, ever saw him out of temper or heard him utter an ill-natured word. He often said that spite and ill-nature were the most expensive luxuries in life; and his advice, then often sought, was given with that clearness and decision, and that absence of all prejudice, which characterised his opinions in after-life.

‘All his friends of his own age were attached to him in no ordinary degree, and they watched every step in his future career with pride and interest.

‘In fact, he was a joyous, open-hearted, considerate friend, willing to contribute to the pleasure and enjoyment of those about him; well knowing his own power, but never intruding it to the annoyance of others, unless he was thwarted or opposed by pretentious ignorance; and then, though at times decided and severe in his remarks, he generally preferred leaving such individuals to themselves, rather than, by noticing them, to give prominence to their deficiencies.

‘His appreciation of character was so exact, and his dislike to anything approaching to vulgarity in thought or action or to undue assumption was so decided, that to be his friend soon became a distinction; and the extent to which his society was sought, not only in private life, but in the scientific world, at this early period, marked strongly the distinguishing features of his mind and character.

‘In 1825 and 1826 he attended the morning lectures at the Royal Institution, and the eagerness and rapidity with which he followed the chemical discoveries which were then being made by Mr. Faraday, showed the facility with which he gained and retained scientific knowledge.

‘To write more would lead me to the events of a later period of his life, in the history of which you require no aid from me; nevertheless, I cannot refrain from adding a few words upon your father’s personal and professional character, which was not, in my opinion, adequately appreciated by the public.

‘His professional friends before his death, and his private friends at all times, well knew the genius, the intense energy, and indefatigable industry with which every principle and detail of his profession was mastered; and both knew and valued the high moral tone which pervaded every act of his life.

‘The public, however, did not see him under the same circumstances.

‘Their imperfect acquaintance with his character arose in a great degree from his disregard of popular approbation, for he was never so satisfied with his own work as to feel himself entitled to receive praise in the adulatory style of modern writing, and he preferred to work quietly in his own sphere, and to rely on the intrinsic merits of his undertakings bringing their reward, rather than to court temporary popularity.

‘The rapidity with which he gained a high position as a civil engineer is the best evidence of his talents. He passed almost direct from boyhood to an equality with any one then in the profession--a position attained by the rapidity and accuracy with which he could apply theory to practice, and support his conclusions by mathematical demonstrations.

‘This knowledge, always used without ostentation, soon placed him above most of his contemporaries; and his intimate acquaintance with the strength and peculiarities of the various materials he had to employ, and of the best and most economical mode of applying them, impressed both directors and contractors with a degree of confidence in his estimates and opinions which no one had before possessed.

‘His power of observation was singularly accurate; he was not satisfied with a hasty or superficial examination, nor with the mere assertion of a fact; his mind required evidence of its correctness before he could receive and adopt it. I may illustrate this by a reference to the experiments he made with French mesmerists, and the pains he took to expose the farce of table-turning and its accompanying follies.

‘My object, however, by this addition to my note, is to dwell upon the fact that he left a mark upon his profession which cannot be obliterated. He set up a high standard of professional excellence, and endeavoured to impress on all who were associated with him, or under him professionally, that to attain the highest honours required the strictest integrity, sound mathematical knowledge, originality and accuracy of thought and expression, both in _viva voce_ descriptions and in designs and working drawings, and a practical acquaintance with the durability and strength of materials, so as to know the best conditions under which each might be applied.

‘It was his excellence in these respects, when still young, which soon earned for him a great reputation as a witness before the Committees of the Houses of Parliament.

‘His calmness and unobtrusive manner, when under severe examination, or while attending public meetings, led many to think him cold, and regardless of the feelings or interests of those with whom he was associated; but nothing was further from his character, as every one knew who was engaged in the consultations upon the result of which future proceedings depended.

‘He was a prudent and cautious, but bold adviser, and a warm-hearted and generous friend.

‘Yours faithfully, ‘W. HAWES.

‘Isambard Brunel, Esq.’

The events of the year 1835 brought with them, not unnaturally, other changes. At the beginning of 1836, he removed to 18 Duke Street, Westminster, a large house looking on St. James’s Park, and now (1870) the last in the street, next to the new India Office.

In July of the same year he married the eldest daughter of the late William Horsley, and granddaughter of Doctor Callcott. Of this marriage there was issue two sons and a daughter, all of whom survive him.

Although, as will be presently mentioned, he afterwards bought some property in Devonshire, the Duke Street house was always his home. He spent his life there, having his offices on the lower floors.

He had no wish to enter Parliament, although it had been more than once suggested to him to do so, and his work prevented his taking an active share, as an inhabitant of Westminster, in the concerns of his neighbourhood.

The only occasion on which he took a prominent part in local affairs was as a special constable in April 1848, when he acted as one of the two ‘leaders’ of the special constables in the district between Great George Street and Downing Street.

He was not without experience of the duties of a special constable, as he had been sworn in during the Bristol riots of 1830, and on that occasion saw active service. Happily, matters were better managed in London, and no actual collision took place between the constables, or the military, and the mob.

* * * * *

The extent to which Mr. Brunel kept his works in his own hands, and under his own superintendence, made it necessary for him to have a large amount of office accommodation; and the inconvenience of having branch offices in the streets near his house led him, in 1848, to enlarge his offices: with this object he added the adjoining house, 17 Duke Street, which he rebuilt. A large room on the ground floor, looking on the Park, was thenceforward his own office, and the room above was made the dining-room. It was decorated in the Elizabethan style, and was to have contained a collection of pictures illustrative of scenes in ‘Shakespeare,’ painted for him by the principal artists of the day. This project was never completely carried out, but several pictures (about ten in all) were painted and hung up, among them the ‘Titania’ of Sir Edwin Landseer. These subjects are again referred to in the following letter:--

February, 1870.

‘My dear Isambard,--You ask me to jot down for you any reminiscences I have of your father’s love and feeling for art.

‘I remember with singular distinctness the first time I ever saw him, when I was a lad of fourteen, and had just obtained my studentship at the Royal Academy. He criticised with great keenness and judgment a drawing which I had with me, and at the same time gave me a lesson on paper straining. From that time till his death he was my most intimate friend. Being naturally imbued with artistic taste and perception of a very high order, his critical remarks were always of great value, and were made with an amount of good humour which softened their occasionally somewhat trying pungency. He had a remarkably accurate eye for proportion, as well as taste for form. This is evinced in every line to be found in his sketch books, and in all the architectural features of his various works.

‘So small an incident as the choice of colour in the original carriages of the Great Western Railway, and any decorative work called for on the line, gave public evidence of his taste in colour; but those who remember the gradual arrangement and fitting up of his house in Duke Street will want no assurance from me of your father’s rare artistic feeling. He passed, I believe, the pleasantest of his leisure moments in decorating that house, and well do I remember our visits in search of rare furniture, china, bronzes, &c., with which he filled it, till it became one of the most remarkable and attractive houses in London. Its interest was greatly increased when he formed that magnificent dining-room, now, with the house of which it was a part, pulled down. This room, hung with pictures, with its richly carved fireplace, doorways, and ceiling, its silken hangings and Venetian mirrors, lighted up on one of the many festive gatherings frequent in that hospitable house, formed a scene which none will forget who had the privilege of taking part in it. When from time to time he went abroad, and especially in his visit to Venice in 1852, he added to his collection by purchases made with great judgment and skill. In buying pictures, your father evinced a taste often found in men of refined mind and feeling--viz. a repugnance to works, however excellent in themselves, where violent action was represented. He preferred pictures where the subject partook more of the suggestive than the positive, and where a considerable scope was left in which the imagination of the spectator might disport itself. This feeling was displayed in a great love of landscape art, and in the keenest appreciation of the beauties of nature. It is an interesting fact to record, and one which I often heard him mention, when his friends were admiring his beautiful grounds at Watcombe, that in the old posting days, when travelling on the cliff road between Teignmouth and Torquay, he constantly stopped the carriage to get out and admire the view which he had discovered from a field at Watcombe, little thinking then that it would ultimately be the site of his intended country home.

‘When your father and I went to Italy together in 1842, posting from Westminster to Rome and back again, I had ample opportunities of observing his love and enthusiasm for nature and art.

‘Overwhelmed as he was with work in England at the time, it was no easy matter for him to leave the country for a couple of months; and I remember that our starting at all was uncertain up to the last moment; and that, an hour before quitting London, it was only by a _coup de théâtre_, which he most adroitly performed, that he escaped the serving of a subpœna, the bearer of which had actually penetrated to the dining-room door in Duke Street.

‘We left London one evening in April 1842. During our journey we constantly passed several consecutive days and nights in the carriage; and I am sure there was not one of our waking hours in which some incident of interest did not occur.

‘I remember your father agreeing with me, that our experiences merely of post-boys and their various characteristics would be worthy of recording in detail--from Newman’s two smart lads, who took us the first stage out of London, on to the genuine “postillon” (boots and all) we found at Calais; then to the wild young brigands (in appearance) who, inspired by the prospect of extra “buon mano,” whirled us along the road from Civita Vecchia towards Rome, and winding up with the stolid German who rose slowly in his stirrups, and distracted us by a melancholy performance on the horn slung round him, and which no entreaty would induce him to give up.

‘We posted from Calais, _viâ_ Paris, to Châlons-sur-Saône, marvelling the whole way whereabouts “La Belle France” was to be found; for a drearier and more utterly monotonous ride of something like 800 miles it is impossible to conceive. From Châlons we went down the river to Lyons, then onwards, visiting Nismes, and through Arles to Toulon.

‘From Toulon we went through Cannes and Nice and along the lovely Cornice road to Genoa. Your father was intensely delighted with this portion of the journey. Those wonderfully picturesque towns, with their roccoco churches looking like toys, and painted all over upon the principle of colour generally developed in that species of art, especially interested him. The streets were so narrow that it was sometimes doubtful whether the carriage could be squeezed through, and more than once it grazed the houses on either side as it passed on.

‘The work for which your father had come to Italy commenced at Genoa, and he was met there by a staff appointed by the Government to accompany him during his stay.

‘While at Genoa he came to me one morning and said, that, in consequence of some delay, he had a week in which to make complete holiday, and gave me the choice of Florence or Rome. I need scarcely say that I chose Rome, and for three days we were in the Eternal City, seeing more in that time than those to whom we related our proceedings could believe.

‘How well do I remember our entering Rome by the gate on the Civita Vecchia road, and standing up in the carriage to get our first view of St. Peter’s, and, having seen it, the blank look of disappointment we turned on each other at the sight! But the interior of the great church as far exceeded our expectations as the exterior had fallen short of them.

‘We were back at Genoa to the minute your father had appointed; and the work being completed there, we went on to Turin. Here we were in time to be present at the Court balls and ceremonies consequent upon the marriage of the present King of Italy.

‘From Turin we proceeded to Milan.

‘At Milan your father parted from his staff, and completed the work he had undertaken as far as it was necessary to do so in Italy. From Milan, therefore, our journey home was one of uninterrupted enjoyment through those glorious Lombard towns to Venice, which happily we reached in a gondola from Mestre, and not by a railway viaduct; then through the Tyrol to Munich, and so down the Rhine to Belgium, reaching home from Antwerp.

‘Thus was completed an expedition in which there was neither hitch nor disagreeable adventure of any kind, and upon which I look back with unmixed pleasure.

‘The next and last time that your father and I journeyed on the Continent together was in April 1848, when he wished to see Paris in Republican garb, and asked me to accompany him.

‘We were there for some days, and, armed with cards of admission, on which our names were inscribed with the prefix of “Citoyen,” heard and saw the various celebrities of the hour.

‘Affectionately yours, J. C. HORSLEY.

‘Isambard Brunel, Esq.’

Within less than a year of Mr. Brunel’s return from his visit to Italy, a strange accident happened to him, which placed his life in great jeopardy.

On April 3, 1843, he was amusing some children at his house by the exhibition of conjuring tricks, when, in pretending to pass a half-sovereign from his ear to his mouth, the coin he had placed in his mouth slipped down his throat. After a few days he began to suffer from a troublesome cough, and on April 18 Sir Benjamin Brodie was consulted.

The nature of the accident and the course of treatment adopted are described in the following letter from Mr. Brunel’s brother-in-law, the late Dr. Seth Thompson, which was published in the ‘Times’ newspaper of May 16, 1843:--

I shall be much obliged by your giving insertion to the following statement of the treatment pursued by Sir Benjamin Brodie in the case of Mr. Brunel, it being the wish of Mr. Brunel and his friends that the true facts should be known, as a just tribute to the skill of this eminent surgeon, and as a guide to future practice. The accident happened on April 3; Sir B. Brodie was consulted on the 18th, and his opinion was that the half-sovereign had passed into the windpipe. The following day Mr. Brunel strengthened this opinion by a simple experiment. He bent his head and shoulders over a chair, and distinctly felt the coin drop towards the glottis; whilst raising himself a violent fit of coughing came on, which ceased after a few minutes. He repeated this a second time, with the same results. A consultation was held on the 22nd, at which it was decided that conclusive evidence existed of the half-sovereign having passed into the windpipe, that it was probably lodged at the bottom of the right bronchus, and that it was movable. It was determined that every effort should be made for its removal, and that for this purpose an apparatus should be constructed for inverting the body of the patient, in order that the weight of the coin might assist the natural effort to expel it by coughing. The first experiment was made on the 25th. The body of the patient being inverted, and the back gently struck with the hand between the shoulders, violent cough came on, but of so convulsive and alarming a nature that danger was apprehended, and the experiment was discontinued. On this occasion the coin was again moved from its situation, and slipped towards the glottis. On the 27th tracheotomy was performed by Sir B. Brodie, assisted by Mr. Aston Key, with the intention of extracting the coin by the forceps, if possible, or, in the event of this failing, with the expectation that the opening in the windpipe would facilitate a repetition of the experiment of the 22nd. On this occasion, and subsequently on May 2, the introduction of the forceps was attended with so much irritation, that it could not be persevered in without danger to life. On the 3rd another consultation was held, when Mr. Lawrence and Mr. Stanley entirely confirmed the views of Sir B. Brodie and Mr. Key, and it was agreed that the experiment of inversion should be repeated as soon as Mr. Brunel had recovered sufficient strength, the incision in the windpipe being kept open. On Saturday, the 13th, Mr. Brunel was again placed on the apparatus, the body inverted, and the back gently struck. After two or three coughs, he felt the coin quit its place on the right side of the chest, and in a few seconds it dropped from his mouth without exciting in its passage through the glottis any distress or inconvenience, the opening in the windpipe preventing any spasmodic action of the glottis.

In this remarkable case the following circumstances appear to be worthy of note--that a piece of gold remained in the air-tube for six weeks, quite movable, and without exciting any inflammatory action, the breathing entirely undisturbed, and the only symptoms of its presence occasional uneasiness on the right side of the chest and frequent fits of coughing; that an accurate diagnosis was formed without being able to obtain any assistance from the stethoscope, although the chest was repeatedly and carefully examined; and also that, a fair trial having been given to the forceps, the application of this instrument to the removal of a body of this peculiar form from the bottom of the bronchus was proved to be attended with great risk to life, while the cautious and well-considered plan of treatment above detailed was attended with complete success, and without risk.

During the time that Mr. Brunel was in danger the public excitement was intense. His high professional position, the extraordinary nature of the accident, and the greatness of the loss, were the result to prove fatal, made his condition and the chances of his recovery an engrossing topic of conversation; and, when the news was spread that ‘it is out,’ the message needed no explanation.

That the result was successful was due, not only to the skill of the surgeons engaged, and to the anxious care with which those who nursed him left nothing undone to ensure his safety, but also to the remarkable coolness which Mr. Brunel himself displayed throughout. From the first he took part in the consultations which were held on his case, and assisted materially in determining the course of treatment which should be pursued.

* * * * *

The ten years which followed were the most prosperous in Mr. Brunel’s life; he had attained to great eminence in his profession, and was still in the enjoyment of robust health. But the results of the gauge controversy and the fierce contests which followed it, and, above all, the failure of the Atmospheric System on the South Devon Railway, caused him grave anxiety and sorrow. Critics have erred greatly in representing him as a man who, in order to accomplish some vast design, thought but little of the distress which follows want of success in commercial enterprises. So far from its being true that Mr. Brunel was indifferent to the interests of his employers, his private journals show that throughout (to use his own words) ‘the incessant warfare in which he was engaged’ he was earnestly desiring peace and endeavouring to secure it, and that in times of difficulty, such as the trial of the Atmospheric System and the launch of the ‘Great Eastern,’ his chief thoughts were for those who would suffer through the failure of his plans.

* * * * *

In the midst of his professional occupations he was able occasionally, though rarely, to enjoy the society of his friends. After the session was over, in 1844 and 1845, he went to Italy on business, and in 1846 to Switzerland for a short holiday. In 1847 the South Devon Railway was occupying his attention, and he determined to take a house at Torquay. While there, the important character of his railway works in Devonshire and Cornwall led him to think of making a more permanent settlement in that part of the country.

After a good deal of hesitation between various places, he fixed upon a spot at Watcombe, about three miles from Torquay, on the Teignmouth turnpike road. He made his first purchase of land in the autumn of 1847; and from that time to within a year of his death the improvement of this property was his chief delight.

He had always a great love and appreciation of beautiful scenery, and in his choice of a place in which to plant and build he provided amply for his complete gratification.

The principal view, which, if the house had been built, would have been the view from the terrace, is one of the loveliest in that part of Devonshire. On one side is the sea, and on the other the range of Dartmoor, while in front is spread undulating country, bounded by the hills on the further side of Torbay, the bay itself looking like a lake, being shut in by the hills above Torquay.

When Mr. Brunel bought this property it consisted of fields divided by hedgerows; but, assisted by Mr. William Nesfield, he laid it out in plantations of choice trees. The occupation of arranging them gave him unfailing pleasure; and, although he could seldom spare more than a few days’ holiday at a time, there can be little doubt that the happiest hours of his life were spent in walking about in the gardens with his wife and children, and discussing the condition and prospects of his favourite trees.[193]

He could not, of course, take a prominent part in the affairs of the parish, but he was always ready to assist in any work that had been taken in hand. He will be long remembered there by his friends in every rank of life.

In purchasing this property in Devonshire, Mr. Brunel had looked forward to retiring gradually from active professional life, ‘to draw in and make room for others,’ and to spend a greater portion of his time in the country.

It may well be questioned whether he would have been happy in giving up work while yet in middle life; but the wisdom of his resolve was not to be put to the test.

From the beginning of the year 1852 the ‘Great Eastern’ steam-ship began to occupy his time and thoughts. As the works progressed he was more and more tied to London; and the large pecuniary investment he had made in the shares of the company caused him to hesitate before proceeding with the building of his house.

Thus the hopes he had formed for making his home in Devonshire faded gradually away, and were at length extinguished by the failure of his health.

* * * * *

Many things had happened in the earlier part of 1857 which gave him pleasure. In June he received, in company with Mr. Robert Stephenson, the honorary degree of Doctor in Civil Law from the University of Oxford.[194] In the summer he paid several visits to Devonshire, and at the beginning of September the floating of the first truss of the Saltash bridge was successfully accomplished.

The history of the launch of the ‘Great Eastern,’ which was commenced in November, has been already told. Throughout all the disappointments he then endured Mr. Brunel took comfort from the sympathy of valued friends, and from those higher sources of consolation on which it was his habit to rely. He paid for his exertions a heavy price, for they left him broken in health and already suffering from the disease of which in a little more than eighteen mouths afterwards he died.[195]

* * * * *

In May 1858 Mr. Brunel went to Vichy, and thence to Switzerland, returning home in the autumn by way of Holland. When at Lucerne he went up the Righi, and was so charmed with it that, instead of spending only a night there, he remained a week, working at the designs for the Eastern Bengal Railway.

It was on his return to England in September that the alarming nature of his illness was ascertained. After anxious consultation with Sir Benjamin Brodie and Dr. Bright, he was ordered to spend the winter in Egypt, in the hope that he might return in the March or April following in restored health.

He was very unwilling to be so long absent from England, especially as a new company had just been formed to finish the ‘Great Eastern,’ and the contracts for her completion were about to be let.

However, it was thought that very serious consequences might follow if he remained at home; and in the beginning of December he left for Alexandria, with his wife and younger son.

Having stayed there a day or two, they went on to Cairo, where they found Mr. Robert Stephenson. He and Mr. Brunel dined together on Christmas Day.

On December 30 the journey up the Nile commenced. On January 21 they arrived at Thebes, and spent some days there. Mr. Brunel was able to ride about on a donkey, and made some sketches of the celebrated ruins in the neighbourhood.[196]

They reached Assouan on February 2, and made preparations for ascending the cataracts. They went as far as Dakkeh, and got back to Assouan on February 19.

The following letter from Mr. Brunel to his sister, Lady Hawes, describes some of the scenes through which he passed:--

Philæ, February 12, 1859.

I now write to you from a charming place; but Assouan, which I left to come here, is also beautiful, and I will speak of that first. It is strange that so little is said in the guide books of the picturesque beauty of these places. Approaching Assouan, you glide through a reef of rocks, large boulders of granite polished by the action of the water charged with sand. You arrive at a charming bay or lake of perfectly still water and studded with these singular jet-black or red rock islands. In the distance you see a continuation of the river, with distant islands shut in by mountains, of beautiful colours, some a lilac sandstone, some the bright red yellow of the sands of the desert. Above the promontories the water excursions are delicious. You enter at once among the islands of the Cataracts, fantastic forms of granite heaps of boulders split and worn into singular shapes.

After spending a week at Assouan, with a trip by land to Philæ, I was so charmed with the appearance of the Cataracts as seen from the shore, and with the deliciously quiet repose of Philæ, that I determined to get a boat, and sleep a few nights there. We succeeded in hiring a country boat laden with dates, and emptied her, and fitted up her three cabins.[197] We put our cook and dragoman and provisions, &c., on board, and some men, and went up the Cataract. It was a most amusing affair, and most beautiful and curious scenery all the way. It is a long rapid of three miles, and perhaps one mile wide, full of rocky islands and isolated rocks. A bird’s-eye view hardly shows a free passage, and some of the more rapid falls are between rocks not forty feet wide--in appearance not twenty. Although they do not drag the boats up perpendicular falls of three or four feet, as the travellers’ books tell you, they really do drag the boats up rushes of water which, until I had seen it, and had then calculated the power required, I should imprudently have said could not be effected. We were dragged up at one place a gush of water, what might fairly be called a fall of about three feet, the water rushing past very formidably, and between rocks seemingly not more than wide enough to let our boat pass, and this only by some thirty-five men at three or four ropes, the men standing in the water and on the rocks in all directions, shouting, plunging into the water, swimming across the top or bottom of the fall, just as they wanted, then getting under the boat to push it off rocks, all with an immense expenditure of noise and apparent confusion and want of plan, yet on the whole properly and successfully. We were probably twenty or thirty minutes getting up this one, sometimes bumping hard on one rock, sometimes on another, and jammed hard first on one side and then on the other, the boat all the time on the fall with ropes all strained, sometimes going up a foot or two, sometimes losing it, till at last we crept to the top, and sailed quietly on in a perfectly smooth lake. These efforts up the different falls had been going on for nearly eight hours, and the relief from noise was delicious. We selected a quiet spot under the temples of Philæ.... Our poultry-yard is on the sandbank, where fowls, pigeons, and turkeys are walking about loose, and, like all animals in this country, perfectly tame. Yes, they walk up and catch a pigeon to be killed when you like. In the midst of these and of the small birds which always walk and fly about us, have been walking for hours this morning three or four large eagles, who, with the politeness peculiar to animals here, pay no attention to our fowls, nor do they to the eagles. But here I am entering on the anomalies and contradictions of Egypt, which would fill volumes.

After leaving Egypt, Mr. Brunel went to Naples and Rome, where he spent Easter, and he returned to England in the middle of May.

When abroad, Mr. Brunel made sight-seeing a pleasure rather than a business; thus in Egypt he preferred to visit frequently the same places, and rather to enjoy that which he knew gave him pleasure, than to hurry about with the object of seeing all that was to be seen. At Philæ he stopped more than a week, and at Thebes he spent more time in a small outlying temple near Karnac than in the great ruin itself. So also at Rome he went frequently to the Colosseum, and he spent many hours in the interior of St. Peter’s.

Shortly after his return to England he went to Plymouth, and over the Saltash bridge and other parts of the Cornwall Railway, which had been opened during his absence abroad.

Although it had by this time become certain that the disease under which he laboured had assumed a fatal character, he continued to give unremitting attention to his various professional duties; and in order to be nearer the ‘Great Eastern,’ he took a house at Sydenham, and removed there with his family in the beginning of August.

Almost every day he went to the great ship and superintended the preparations for getting her to sea. She was advertised to sail on September 6, and Mr. Brunel had intended going round in her to Weymouth.

He was on board early on the morning of the 5th, and his memorandum book has, under that date, an entry of some unfinished work which had to be looked after. Towards midday he felt symptoms of failing power, and went home to his house in Duke Street, when it became evident that he had been attacked with paralysis.

* * * * *

At one time it seemed possible that he might recover; but on the tenth day after his seizure, Thursday, September 15, all hope was taken away. In the afternoon he spoke to those who watched around him, calling them to him by their names; as evening closed in he gradually sank, and died at half-past ten, quietly and without pain.

* * * * *

The funeral was on September 20, at the Kensal Green Cemetery.

Along the road leading to the chapel many hundreds of his private and professional friends, his neighbours among the tradespeople of Westminster, the Council of the Institution of Civil Engineers, and the servants of the Great Western Railway Company, had assembled, and, with his family, followed his body to its place of burial, in the grave of his father and mother.[198]

It would be improper here to attempt to enter into a general criticism of Mr. Brunel’s works, or to determine the position which he is entitled to occupy among civil engineers. That task has yet to be accomplished, and must be undertaken by those who can claim to be impartial judges. It has been the object of this book to provide, as far as possible, the materials on which a just judgment of his career can be based.

But it may be permitted, in conclusion, to place on record the following testimony to the high position held by Mr. Brunel in the esteem of his contemporaries.

* * * * *

On November 8, 1859, at the first meeting of the Institution of Civil Engineers after the death of Mr. Brunel and of Mr. Robert Stephenson, Mr. Joseph Locke, M.P., the President, rose and said--

‘I cannot permit the occasion of opening a new session to pass without alluding to the irreparable loss which the Institution has sustained by the death, during the recess, of its two most honoured and distinguished members.

‘In the midst of difficulties of no ordinary kind, with an ardour rarely equalled, and an application both of body and mind almost beyond the limit of physical endurance, in the full pursuit of a great and cherished idea, Brunel was suddenly struck down, before he had accomplished the task which his daring genius had set before him.

‘Following in the footsteps of his distinguished parent, Sir Isambard Brunel, his early career, even from its commencement, was remarkable for originality in the conception of the works confided to him. As his experience increased, his confidence in his own powers augmented; and the Great Western Railway, with its broad-gauge line, colossal engines, large carriages, and bold designs of every description, was carried onward, and ultimately embraced a wide district of the country.

‘The same feeling induced, in steam navigation, the successive construction of the “Great Western” steamer, the largest vessel of the time, until superseded by the “Great Britain,” which was in its turn eclipsed by the “Great Eastern,” the most gigantic experiment of the age.

‘The Great Ship was Brunel’s peculiar child; he applied himself to it in a manner which could not fail to command respect; and, if he did not live to see its final and successful completion, he saw enough, in his later hours, to sustain him in the belief that his idea would ultimately become a triumphant reality.

‘The shock which the loss of Brunel created was yet felt, when we were startled by an announcement that another of our esteemed members had been summoned from us.[199]

* * * * *

‘It is not my intention at this time to give even an outline of the works achieved by our two departed friends. Their lives and labours, however, are before us; and it will be our own fault if we fail to draw from them useful lessons for our own guidance. Man is not perfect, and it is not to be expected that he should be always successful; and, as in the midst of success we sometimes learn great truths before unknown to us, so also we often discover in failure the causes which frustrate our best directed efforts. Our two friends may probably form no exception to the general rule; but, judging by the position they had each secured, and by the universal respect and sympathy which the public has manifested for their loss, and remembering the brilliant ingenuity of argument, as well as the more homely appeals to their own long experience, often heard in this hall, we are well assured that they have not laboured in vain.

‘We, at least, who are benefited by their successes, who feel that our Institution has reason to be proud of its association with such names as Brunel and Stephenson, have a duty to perform; and that duty is, to honour their memory and emulate their example.’

APPENDIX I.

(_See Chapter V. on the Broad Gauge, p. 99._)

_Report to the Board of Directors of the Great Western Railway Company._

August 1838.

GENTLEMEN,--As the endeavour to obtain the opinions and reports of Mr. Walker, Mr. Stephenson, and Mr. Wood, prior to the next half-yearly meeting, has not been successful, I am anxious to record more fully than I have previously done, and to combine them into one report, my own views and opinions upon the success of the several plans which have been adopted at my recommendation in the formation and in the working of our line; and in justice to myself and to these plans, and indeed to enable others to arrive at any just conclusion as to the result which has been attained, or as to the probable ultimate success or advantages of the system, it is necessary that I should enter very fully, I fear even tediously, into a recapitulation of the circumstances, peculiar to this railway, which led to the consideration and the adoption of these plans, which some call innovations and wide deviations from the results of past experience, but the majority of which I will undertake to show are merely adaptations of those plans to our particular circumstances.

It will be necessary also that I should refer to all the numerous difficulties which we have had to encounter, which have necessarily prevented the perfect working of these plans in the first instance, but which have been overcome, or which are gradually and successively diminishing; and, finally, I am prepared to show that, notwithstanding the novelty of the circumstances, and the difficulties and delays which at the outset invariably attend any alteration, however necessary, or however desirable, from the accustomed mode of proceeding, and notwithstanding the violent prejudices excited against us, and the increased difficulties caused by these prejudices, the result is still such as to justify the attempt which has been made, and to show that in the main features, if not in all the details, the system hitherto followed is good, and ought to be pursued.

The peculiarity of the circumstances of this railway, to which I would more particularly refer, and which have frequently been mentioned, consists in the unusually favourable gradients and curves which we have been able to obtain. With the capability of carrying the line upwards of fifty miles out of London on almost a dead level, and without any objectionable curve, and having beyond this, and for the whole distance to Bristol, excellent gradients, it was thought that unusually high speed might easily be attained, and that the very large extent of passenger traffic which such a line would certainly command would ensure a return for any advantages which could be offered to the public, either in increased speed or increased accommodations. With this view every possible attention was paid to the improvement of the line as originally laid down in the parliamentary plans. We ultimately succeeded in determining a maximum gradient of 4 feet per mile, which could be maintained for the unusual distance, before mentioned, of upwards of fifty miles from London, and also between Bristol and Bath, comprehending those parts of the line on which the principal portion of the passenger traffic will be carried. The attainment of high speed appeared to involve the question of the width of gauge, and on this point accordingly I expressed my opinion at a very early period.

It has been asserted that 4 feet 8 inches, the width adopted on the Liverpool and Manchester Railway, is exactly the proper width for all railways, and that to adopt any other dimension is to deviate from a positive rule which experience has proved correct; but such an assertion can be maintained by no reasoning. Admitting, for the sake of argument, that, under the particular circumstances in which it has been tried, 4 feet 8 inches has been proved the best possible dimension, the question would still remain--What are the best dimensions under the circumstances?

Although a breadth of 4 feet 8 inches has been found to create a certain resistance on curves of a certain radius, a greater breadth would produce only the same resistance on curves of greater radius. If carriages and engines, and more particularly if wheels and axles of a certain weight, have not been found inconvenient upon one railway, greater weights may be employed and the same results obtained on a railway with better gradients. To adopt a gauge of the same number of inches on the Great Western Railway as on the Grand Junction Railway, would in fact amount practically to the use of a different gauge in similar railways. The gauge which is well adapted to the one is not well adapted to the other, unless, indeed, some mysterious cause exists which has never yet been explained for the empirical law which would fix the gauge under all circumstances.

Fortunately this no longer requires to be argued, as too many authorities may now be quoted in support of a very considerable deviation from this prescribed width, and in every case this change has been an increase. I take it for granted that, in determining the dimensions in each case, due regard has been had to the curves and gradients of the line, which ought to form a most essential, if not the principal, condition.

In the Report of the Commissioners upon Irish Railways, the arguments are identically the same with those which I used when first addressing you on the subject in my Report of October 1835. The mechanical advantage to be gained by increasing the diameter of the carriage-wheels is pointed out, the necessity, to attain this, of increasing the width of way, the dimensions of the bridges, tunnels, and other principal works, not being materially affected by this; but, on the other hand, the circumstance which limits this increase being the curves on the line, and the increased proportional resistance on inclinations (and on this account it is stated to be almost solely applicable to very level lines); and, lastly, the increased expense, which could be justified only by a great traffic.

The whole is clearly argued in a general point of view, and then applied to the particular case, and the result of this application is the recommendation of the adoption of 6 feet 2 inches on the Irish railways. Thus, an increase in the breadth of way to attain one particular object--viz. the capability of increasing the diameter of the carriage-wheels without raising the bodies of the carriages--is admitted to be most desirable, but is limited by certain circumstances, namely, the gradients and curves of the line, and the extent of traffic.

Every argument here adduced, and every calculation made, would tend to the adoption of about 7 feet on the Great Western Railway.

The gradients of the lines laid down by the Irish Commission are considerably steeper than those of the London and Birmingham Railway, and four and five times the inclination of those on the Great Western Railway; the curves are by no means of very large radius, and indeed the Commissioners, after fixing the gauge of 6 feet 2 inches, express their opinion, that upon examination into the question of curves, with a view to economy, they do not find that the effect is so injurious as might have been anticipated, and imply therefore that curves, generally considered of small radius on our English lines, are not incompatible with the 6 feet 2 inch gauge; and, lastly, the traffic, instead of being unusually large, so as to justify any expense beyond that absolutely required, is such as to render assistance from Government necessary to ensure a return for the capital embarked. As compared with this, what are the circumstances in our case?

The object to be attained is the placing an ordinary coach body, which is upwards of 6 feet 6 inches in width, between the wheels. This necessarily involves a gauge of rail of about 6 feet 10½ inches to 6 feet 11 inches, but 7 feet allows of its being done easily; it allows, moreover, of a different arrangement of the body: it admits all sorts of carriages, stage-coaches, and carts to be carried between the wheels. And what are the limits in the case of the Great Western Railway, as compared to those on Irish railways? Gradients of one-fifth the inclination, very favourable curves, and probably the largest traffic in England.

I think it unnecessary to say another word to show that the Irish Commissioners would have arrived at 7 feet on the Great Western Railway by exactly the same train of argument that led them to adopt 6 feet 2 inches in the case then before them.

All these arguments were advanced by me in my first Report to you, and the subject was well considered. The circumstance of the Great Western Railway, and other principal railways likely to extend beyond it, having no connection with other lines then made, leaving us free from any prescribed dimension, the 7-feet gauge was ultimately determined upon. Many objections were certainly urged against it: the deviation from the established 4 feet 8 inches was then considered as the abandonment of the principle: this, however, was a mere assertion, unsupported even by plausible argument, and was gradually disused; but objections were still urged, that the original cost of construction of all the works connected with the formation of the line must be greatly increased; that the carriages must be so much stronger; that they would be proportionally heavier; that they would not run round the curves, and would be more liable to run off the rails; and particularly, that the increased length of the axles would render them liable to be broken: and these objections were not advanced as difficulties which, as existing in all railways, might be somewhat increased by the increase of gauge, but as peculiar to this, and fatal to the system.

With regard to the first objection, namely, the increased cost in the original construction of the line, if there be any, it is a question of calculation which is easily estimated, and was so estimated before the increased gauge was determined upon. Here, however, preconceived opinions have been allowed weight in lieu of arguments and calculations; cause and effect are mixed up, and without much consideration it was assumed at once that an increased gauge necessarily involved increased width of way, and dimensions of bridges, tunnels, &c.

Yet such is not the case within the limits we are now treating of: a 7-feet rail requires no wider bridge or tunnel than a 5-feet; the breadth is governed by a maximum width allowed for a loaded waggon, or the largest load to be carried on the railway, and the clear space to be allowed on either side beyond this.

On the Manchester and Liverpool Railway this total breadth is only 9 feet 10 inches, and the bridge and viaducts need only have been twice this, or 19 feet 8 inches; 9 feet 10 inches was found, however, rather too small, and in the London and Birmingham, with the same width of way, this was increased to 11 feet by widening the interval between the two rails.

In the space of 11 feet, allowed for each rail, a 7-feet gauge might be placed just as well as a 5-feet, leaving the bridges, tunnels, and viaducts exactly the same; but 11 feet was thought by some still too narrow: and when it is remembered that this barely allows a width of 10 feet for loads, whether of cotton, wool, agricultural produce, or other light goods, and which are liable also to be displaced in travelling, 13 feet (which has been fixed upon in the Great Western Railway, and which limits the maximum breadth, under any circumstances, to about 12 feet) will not be found excessive.

It is this which makes the minimum width, actually required under bridges and tunnels, 26 feet instead of 22 feet, and not the increased gauge.

The earthwork is slightly affected by the gauge, but only to the extent of 2 feet on the embankment, and not quite so much in the cuttings; but what, in practice, has been the result? The bridges over the railway on the London and Birmingham are 30 feet, and the width of viaducts 28 feet; on the Great Western Railway they are both 30 feet; no great expense is therefore incurred on these items, and certainly a very small one compared to the increased space gained, which, as I have stated, is from 10 to 12 feet. In the tunnels exists the greatest difference; on the London and Birmingham Railway, which I refer to as being the best and most analogous case to that of the Great Western Railway, the tunnels are 24 feet wide. On the Great Western Railway the constant width of 30 feet is maintained, more with a view of diminishing the objections to tunnels, and maintaining the same minimum space which hereafter may form a limit to the size and form of everything carried on the railway, than from such a width being absolutely necessary.

Without pretending to find fault with the dimensions fixed, and which have, no doubt, been well considered, upon the works on other lines, I may state that the principle which has governed has been to fix the minimum width, and to make all the works the same, considering it unnecessary to have a greater width between the parapet walls of a viaduct, which admits of being altered, than between the sides of a tunnel which cannot be altered.

The embankments on the London and Birmingham Railway are 26 feet, on the Great Western 30 feet, making an excess of about six and a half per cent. on the actual quantity of earthwork.

The difference in the quantity of land required is under half an acre to a mile. On the whole, the increased dimensions from 10 to 12 feet will not cause any average increased expense in the construction of the works, and purchase of land, of above seven per cent.--eight per cent. having originally been assumed in my Report in 1835 as the excess to be provided for.

With respect to the weight of the carriages, although we have wheels of 4 feet diameter, instead of 3 feet, which, of course, involves an increased weight quite independent of the increase of width, and although the space allowed for each passenger is a trifle more, and the height of the body greater, yet the gross weight per passenger is somewhat less.

Tons cwt. qrs. lbs.

A Birmingham first-class coach weighs 3 17 2 0 Which with 18 passengers at 15 to the ton 1 4 0 0 ---------------- 5 1 2 0 Or 631 lbs. per passenger ================

A Great Western first-class weighs 4 14 0 0 And with 24 passengers 1 12 0 0 ---------------- 6 6 0 0 Or 588 lbs. per passenger ================

And our 6-wheeled first-class 6 11 0 0 With 32 passengers 2 2 2 0 ---------------- 8 13 2 0 Or 600 lbs. per passenger ================

Being an average of 594 lbs. on the two carriages.

This saving of weight does not arise from the increased width, and is notwithstanding the increased strength of the framing and the increased diameter and weight of the wheels; I have not weighed our second-class open carriages, but I should think the same proportion would exist.

As to the breaking of axles or running off the line, the practical result has been that, from some cause or other, we have been almost perfectly free from those very objections which have been felt so seriously on some other lines. Far from breaking any engine axles, not even a single cranked axle has been strained, although the engines have been subjected to rather severe trials. One of our largest having, a short time back, been sent along the line at night, when it was not expected, came in collision with some ballast waggons, and was thrown off the line nearly 6 feet; none of the axles were bent, or even strained in the least, although the front of the carriage, a piece of oak of very large scantling, was shattered. After ten weeks’ running, one solitary instance has occurred of a carriage in a train getting off the line and dragging another with it, and which was not discovered till after running a mile and a half. As the carriage was in the middle of the train, and one end of the axle was thrown completely out of the axle guard, there must evidently have been some extraordinary cause--possibly a plank thrown across the railway by a blow from the carriage which preceded, and which might have produced the same effect on any railway; and at any rate it was a strong trial to the axle, which was not broken, but merely restored to its place, and the carriage sent on to London. The same mode of reasoning which has by some been used in favour of the 4 feet 8 inches gauge, if applied here, would prove that long axles are stronger than short, and wide rails best adapted for curves. All that I think proved, however, is this--that the increased tendency of the axles to break, or of the wheels to run off the rails, is so slight that it is more than counterbalanced by the increased steadiness from the width of the base, and the absence of those violent strains which arise from irregularity on the gauge and the harshness of the ordinary construction of rails. In fact, not one of the objections originally urged against the practical working of the wide gauge has been found to exist, while the object sought for is obtained, namely, the capability of increasing at any future period the diameter of the wheels, which cannot be done, however desirable it may hereafter be found, with the old width of rail. This may be said to be only prospective; but, in the meantime, contingent advantages are sensibly felt in the increased lateral steadiness of the carriages and engines, and the greater space which is afforded for the works of the locomotives. And here I wish particularly to call your attention to the fact that this prospective advantage--this absence of a most inconvenient limit to the reduction of the friction, which, with our gradients, forms four-fifths or eighty per cent. of the total resistance--was the object sought for, and that, at the time of recommending it, I expressly stated as follows:--‘I am not by any means prepared at present to recommend any particular size of wheel, or even any great increase of the present dimensions. I believe they _will_ be materially increased; but my great object would be in every possible way to render each part _capable_ of improvement, and to remove what appears an obstacle to any great progress in such a very important point as the diameter of the wheels, upon which the resistance, which governs the cost of transport and the speed that may be obtained, so materially depends.’

These advantages were considered important by you, they are now considered so by many others; and certainly everything which has occurred in the practical working of the line confirms me in my conviction that we have secured a most valuable power to the Great Western Railway, and that it would be folly to abandon it.

The next point I shall consider is the construction of the engines, the modifications in which, necessary to adapt them to higher speeds than usual, have, like the increased width of gauge, been condemned as innovations.

I shall not attempt to argue with those who consider any increase of speed unnecessary. The public will always prefer that conveyance which is most perfect, and speed within reasonable limits is a material ingredient in perfection in travelling.

A rate of thirty-five to forty miles an hour is not unfrequently attained at present on other railways in descending planes, or with light loads on a level, and is found practically to be attended with no inconvenience. To maintain such a speed with regularity on a level line, with moderate loads, is therefore quite practicable, and unquestionably desirable. With this view the engines were constructed, but nothing new was required or recommended by me.

A certain velocity of the piston is considered the most advantageous.

The engines intended for slow speeds have always had the driving wheels small in proportion to the length of stroke of the piston. The faster engines have had a different proportion; the wheels have been larger, or the strokes of the piston shorter. From the somewhat clamorous objections raised against the large wheels, and the construction of the Great Western Railway engines, and the opinions rather freely expressed of my judgment in directing this construction, it would naturally be supposed that some established principle had been departed from, and that I had recommended this departure.

The facts are, that a certain velocity of piston being found most advantageous, I fixed this velocity, so that the engines should be adapted to run thirty-five miles an hour, and capable of running forty--as the Manchester and Liverpool Railway engines are best calculated for twenty to twenty-five, but capable of running easily up to thirty and thirty-five miles per hour; and fixing also the load which the engine was to be capable of drawing, I left the form of construction and the proportions entirely to the manufacturers, stipulating merely that they should submit detail drawings to me for my approval. This was the substance of the circular, which, with your sanction, was sent to several of the most experienced manufacturers. Most of these manufacturers, of their own accord, and without previous communication with me, adopted the large wheels, as a necessary consequence of the speed required. The recommendation coming from such quarters, there can be no necessity for defending my opinion in its favour; neither have I now the slightest doubt of its correctness. As it has been supposed that the manufacturers may have been compelled or induced by me to adopt certain modes of construction, or certain dimensions, in other parts by a specification--a practice which has been adopted on some lines--and that these restrictions may have embarrassed them, I should wish to take this opportunity to state distinctly that such is not the case. I have indeed strongly recommended to their consideration the advantages of having very large and well-formed steam passages, which generally they have adopted, and with good results; and with this single exception, if it can be considered one, they have been left unfettered by me (perhaps too much so) and uninfluenced, except indeed by the prejudices and fears of those by whom they have been surrounded, which have by no means diminished the difficulties I have had to contend with.

The principal proportions of these engines being those which have been recommended by the most able experimentalists and writers, and these having been adopted by the most experienced makers, it is difficult to understand who can constitute themselves objectors, or what can be their objections.

Even if these engines had not been found effective, at least it must be admitted that the best and most liberal means had been adopted to procure them; but I am far from asking such an admission. The engines, I think, have proved to be well adapted to the particular task for which they were calculated--namely, high speeds--but circumstances prevent their being beneficially applied to this purpose at present, and they are, therefore, working under great disadvantages. An engine constructed expressly for a high velocity cannot, of course, be well adapted to exert great power at a low speed; neither can it be well adapted for stopping frequently and regaining its speed. But such was not the intention when these engines were made, neither will it be the case when the arrangements on the line are complete; in the meantime, our average rate of travelling is much greater than it was either on the Grand Junction or the Birmingham Railway within the same period of the opening. I have but one serious objection to make to our present engines, and for this, strange as it may seem, I feel that we are mainly indebted to those who have been most loud in their complaints--I refer to the unnecessary weight of the engines. There is nothing in the wide gauge which involves any considerable increased weight in the engine. An engine of the same power and capacity for speed, whether for a 4-feet 8-inch rail, or for a 7-feet rail, will have identically the same boiler, the same fire-box, the same cylinder and piston, and other working gear, the same side frames, and the same wheels; the axles and the cross-framing will alone differ, and upon these alone need there be any increase; but, if these were doubled in weight, the difference upon the whole engine would be immaterial. But the repeated assertion, frequently professing to come from experienced authorities, and repeated until it was supposed to be proved, that the increased gauge must require increased strength and great power, was not without its indirect effect upon the manufacturers. Unnecessary dimensions have been given to many parts, and the weight thereby increased--rather tending, as I believe, to diminish than to add to the strength of the whole. I thought then, and I believe now, that it would have been unwise in this case to have resisted the general opinion, and taken upon myself the responsibility which belonged to the manufacturers; but I need not now hesitate to say that a very considerable reduction may be effected, and that no such unusual precautions are necessary to meet these anticipated strains and resistances--such being, in fact, imaginary. It cannot surprise anybody that, under such circumstances, attention was more occupied in endeavouring to meet these imaginary prejudiced objections, than in boldly taking advantage of the new circumstances, and that a piece of machinery constructed under such disadvantages was not likely to be a fair sample of what might be done. I am happy to say, however, that the result of the trials that have been made has entirely destroyed all credit in these alarmists with the manufacturer, and that we may hope in future to have the benefits of the free exercise of the intelligence and practical knowledge of engine-manufacturers.

The mode of laying the rails is the next point which I shall consider. It may appear strange that I should again in this case disclaim having attempted anything perfectly new; yet regard to truth compels me to do so. I have recommended, in the case of the Great Western, the principle of a continuous bearing of timber under the rail, instead of isolated supports--an old system recently revived, and as such I described it in my Report of January 1836; the result of many hundred miles laid in this manner in America, and of some detached portions of railways in England, was quite sufficient to prove that the system was attended with many advantages; but since we first adopted it these proofs have been multiplied--there need now be no apprehension. There are railways in full work, upon which the experiment has been tried sufficiently to prove beyond doubt, to those willing to be convinced, that a permanent way in continuous bearings of wood may be constructed, in which the motion will be much smoother, the noise less, and consequently--for they are effects produced by the same cause--the wear and tear of the machinery much less. Such a plan is certainly best adapted for high speeds, and this is the system recommended by me and adopted on our road. There are, no doubt, different modes of construction, and that which I have adopted as an improvement upon others may, on the contrary, be attended with disadvantages. For the system I will strenuously contend.

But I should be sorry to enter with any such determined feeling into a discussion of the merits of the particular mode of construction. I would refer to my last Report for the reasons which influenced me, and the objects I had in view in introducing the piling; that part which had been made under my own eye answered fully all my expectations. Here the piles did answer their purpose, and no inconvenience resulted from their use. The difficulties which we have since encountered, the bad state in which the line was for a considerable time, and which is only recently improved, have undoubtedly been aggravated, if not caused, by these piles; but not, as I believe, from a defect in the principle as applied in our case, where the line is mostly in cutting, or on the surface, but from defective execution; for, notwithstanding the determination to allow sufficient time for this most important operation, yet, to make up for previous delays and loss of time, it became necessary at last to force forward the work more rapidly than was at all consistent with due care in the execution; and during the whole of this period I was most unfortunately prevented by a serious accident from even seeing the work almost until the day of opening, when I ought to have personally superintended the whole. I do not mean that the work was neglected by those whose duty it was to supply my place--far from it; but in such a case, a new work cannot be properly directed except under the eye of the master. Following exactly the plan which had succeeded on the first piece completed, several serious faults were committed. A much greater density and firmness of packing is required than was previously supposed; the mode of packing adopted, and the material selected, in the first instance, have proved defective elsewhere; and over a great extent in the line, particularly in the clay cuttings, and where the work was at last most hurried, it has been badly executed. But many parts have stood well from the commencement; others are fast improving; and I have the satisfaction, although a very painful one, of seeing that if, in the first instance, a foundation of coarse gravel had been everywhere well rammed in before the timbers had been laid, and the packing formed upon this, we should, from the outset, have obtained as solid a road as we have now over a great part of the line. What we have been able to effect since the opening of the line has necessarily been a slow, expensive, and laborious operation. We have been compelled to open the ground, and excavate it to a depth of 18 inches under the longitudinal timbers, and this without interrupting the traffic: to remove the whole of the material thus obtained from off the line, and to replace it by coarse ballast; and not having the means of sufficiently consolidating this ballast by ramming while the timber is in its place, the packing has to be repeated once or twice after it has been compressed by the passing of the trains. This new packing, however, does stand, and in a few weeks I expect the line will be in a very different state from that in which it has been, or indeed now is. From what I have described as the result which can now be, and might have been, obtained from the commencement, it will be inferred that I am disposed still to defend the system of piling. I certainly could not abandon it from conviction of its inefficiency, for I see proofs of the contrary; and I feel that under similar circumstances I could now prevent the mischief which has occurred. Upon that portion of the line where the permanent way must next be formed, piling could not be resorted to, the ground being a solid hard chalk for many miles. I had intended, however, recommending the same principle, but in a different form, holding down the longitudinals by small iron rods driven into the chalk; but the same objection could not exist, because the chalk cannot yield under the timbers like clay, or even gravel. But I should wish most anxiously to avoid anything like an obstinate adherence to a plan, if the object which I believe essential can be obtained by other means, particularly when, that plan being my own, I may be somewhat prejudiced in its favour. I find that the system of piling involves considerable expenses in the first construction, and requires perhaps too great a perfection in the whole work, and that if the whole or a part of this cost were expended in increased scantling of timber and weight of metal, that a very solid continuous rail would be formed.

For this as a principle, as for the width of gauge, I am prepared to contend, and to stand or fall by it, believing it to be a most essential improvement, where high speeds are to be obtained. I strongly urge upon you not to hesitate upon these two main points, which, combined with what may be termed the natural advantages of the line, will eventually secure to you a superiority which, under other circumstances, cannot be obtained.

As regards the expense of forming the permanent way on this principle, I am quite prepared to maintain what I have on a former occasion advanced: that even on the system which we have adopted between London and Maidenhead, the total cost does not materially exceed that of a well-constructed line with stone blocks. I did not make in the outset an exact estimate of the cost of either mode; I was unable to obtain the cost which has actually been incurred on other lines; but a comparative estimate was made, and the result of that comparison led me to state that the one might exceed the other by 500_l._ a mile. The actual cost of our permanent way appears, by the detailed account which has been made out, to have been above 9,000_l._, including expenses of under-draining and forming the surfaces which cannot be included in the cost given in other cases, because that drainage (although I believe generally forming part of the plan) is not yet constructed. This sum includes the sidings at the stations, switches, joints, and other contingencies, and also the expenses incurred during the first month of working the line, and which, as I have before stated, consisted in removing and replacing work which had been improperly executed. These items will make a considerable reduction; and besides these, larger reductions may be effected in parts of the work which were new, and, from the circumstances naturally attending a first attempt, were not so economically conducted as they might be, or indeed, as they were towards the close of the works, when the different parts were let by contract. Taking the prices at which the work was latterly actually executed, 8,000_l._ per mile would be a liberal allowance for our future proceeding, even adopting the same system; and with a modified system, such as that suggested of simple longitudinal bearers of large scantling, and a rail of fifty-four pounds per yard, at the present high price of iron, the cost, calculated upon our actual past expenditure, would not exceed 7,400_l._ per mile. This, I am aware, is a larger sum than that which has usually been assumed as the cost of the permanent way. I cannot prove that others have cost more, or even so much as this, as I have nothing but the published accounts to refer to; but this I can state, and prove if necessary, that rails and blocks, such as are now being adopted on the Manchester and Liverpool Railway, would upon our line cost at least as much.

The prime cost of rails and chairs delivered on the line would alone amount to half the money; and nothing is, perhaps, more certain than that the experience of other lines within the last two or three years has proved that this part of the construction of a railway is unavoidably much more expensive than was ever calculated for at the time our estimates were made.

I am, gentlemen, your obedient servant,

(Signed) I. K. BRUNEL.

APPENDIX II.

(_See Chapter IX. on the ‘Great Britain’ Steam-Ship, p. 254._)

_Report to the Directors of the Great Western Steam-Ship Company._

October 1840.

GENTLEMEN,--I have now the pleasure to lay before you the result of the different experiments which I have made, and of the best consideration I have been enabled to give to the subject of the screw propeller.

The observations which I have to make are naturally divided under two principal heads, namely: first, the simple question of the applicability and efficiency of the screw considered merely as a means of propelling a vessel, compared with the ordinary paddlewheel; and, secondly, the general advantages or disadvantages attending its use.

The consideration of the comparative efficiency of the screw as a means of propelling, of course embraces the whole question, not merely of the effect produced, but also that of the proportionate power absorbed in producing that effect.

With respect to the mere effect of a screw, the performance of the ‘Archimedes’ has proved, in a satisfactory and undeniable manner, that a screw acting against the water with a surface even much smaller than that offered by the paddle-boards of a well-proportioned paddlewheel, will propel the ship at a very fair speed, but at what expense of power this effect has been produced is not so evident.

I shall first examine into the principal cause of what amounts practically to a loss of power, and which is common in a greater or less degree to all modes of propelling a vessel by exerting a pressure against the water as against a fixed point.

The resistance, whether to the surface of a screw, or of a paddle-board, or of the blade of an oar, or any other propelling body, offered by the fluid against which it acts, is of course not perfect, and there is a certain amount of yielding, commonly called the slip, of the paddlewheel; the amount thus slipped causes a considerable waste of power, inasmuch as the full power of the engine is expended through the entire space passed over by the paddles or other propelling surface, while the useful effect produced is only equal to the same power expended over the space through which the vessel passes: this loss frequently amounts to one-quarter, and even one-third, of the whole power employed. To investigate theoretically the amount of slip due to any given form and quantity of surface, involves much more complicated calculations than have generally been applied, and would indeed require data which we hardly possess; but fortunately we have had the means of making experiments, the results of which enable us to determine the comparative slip of the paddle and of the screw, with sufficient accuracy for all practical purposes.

The screw in use on board the ‘Archimedes’ is 5 feet 9 inches diameter, with a pitch of 8 feet--that is to say, in making one revolution the thread of the screw advances 8 feet; the area of the screw, considered as a disc of the same diameter, or the extent of the surface of water which is acted upon in the direction of the axis of the vessel, is therefore about 26 feet, without deducting the section of the shaft-bearing, &c. The midship section of the vessel when I experimented upon her was, according to Mr. Patterson’s estimate, 122 feet; the ratio of the resisting surface to the midship section being therefore as 1 to 4·7, which is a small proportion; and the form of the vessel is by no means peculiarly good as a steamboat. This proportion of propelling surface to midship section is much smaller--that is, the area of the screw is much less in proportion to the size of the vessel than is the area of paddle-boards immersed in steamboats generally.

The average paddle-board immersed and really effective is rather difficult to estimate, as allowances must be made for the disturbance of the water, when the wheel is in motion; but this average in the ‘Great Western’ measured perpendicularly--that is, allowing for the obliquity of the paddle--cannot be less than 180 to 200 feet, say only 180, while the midship section averages about 462 feet; the surface of paddle is therefore about 1/2·56 of the midship section.

I will now give the comparative effects of these different propelling surfaces in these two cases.

I have made very accurate experiments upon the comparative rate of the ‘Archimedes,’ and of the space passed through by the screw, and was enabled to determine this ratio with great certainty.

The average of a number of trials gave the following results:

Rate of ship, 50,867 feet per hour, or about 8⅓ knots.

Space passed through by screw due to the number of revolutions, 65,685 feet.

The average rate of vessel being to that of screw therefore as 1 to 1·2913.

In the performances of the ‘Great Western,’ upon an average of 20 voyages the ratio has been as 1 to 1·2997; but, separating from these 20 such voyages as were unusually short or long, and taking only such as, occupying 14, 15, or 16 days, may be considered as giving a fair average of the speed of the ship when not adversely affected by the wind or heavy seas, the average of these 13 voyages give 1 to 1·283; and leaving out again those of 16 days, and taking only 8 voyages of 14 and 15 days, the average gives a ratio of 1 to 1·27187.

Of these, 5 voyages of 15 days give 1 to 1·29077, and 3 " 14 " 1 to 1·23901.

The last three, however, were short passages and homeward, when the currents and winds have been in favour, and consequently we may safely say that the ratio must be above 1 to 1·239; and after making every allowance for the effect of swell and other impediments (the experiments upon the ‘Archimedes’ being made in smooth water), the average of the 8 (5 of which were homeward voyages with favourable current and wind and the vessel in good trim), giving a ratio of 1 to 1·27, may be taken as a fair average.

The comparison between the ‘Archimedes’ and the ‘Great Western’ will therefore stand thus--

Area of Propelling Difference of Speed of Surface, the Midship Vessel and Propelling Section being 1·0. Surface, or amount of Slip, the ratio of Vessel being 1·0.

‘Archimedes,’ screw 0·203 0·2913 ‘Great Western,’ paddle 0·391 0·2708

Showing an amount of slip in the ‘Great Western’ very nearly equal to that of the ‘Archimedes,’ while the ratio of the propelling surface to the midship section in the case of the screw is little more than half that of the paddle-boards in the ‘Great Western.’

In taking the average of the eight voyages of the ‘Great Western’ with favourable winds as I have done, I believe I have made full allowance for the different circumstances of smooth water and sea; but there is ample room in the above comparison to make even greater allowance for these circumstances, and still to leave a result which would prove that with _similar areas_ the screw would meet with at least equal, if not a greater resistance, and consequently will slip as little or less than the ordinary paddle-board.

I subjoin a table also, taken from a well-known work on the steam-engine (Tredgold’s), of the slip of a number of vessels, of which in every case the surface of paddle immersed is far greater in proportion to the midship section than that of the screw in the ‘Archimedes.’

_Rate of Paddle, that of Ship being_ 1.

Medea 1·595 Flamer 1·483 Firebrand 1·501 Columbine 1·529 Salamander 1·200[200] Dee 1·366 Firefly 1·364 Firebrand, as altered 1·295 Phito 1·215 Monarch 1·323 Magnet 1·310 Meteor 1·490 Carron 1·287 Average 1·381

Great Western 1·27 Archimedes 1·29

This list shows that the result in the ‘Great Western,’ with which ship I have made the comparison, is in itself a favourable one, and that compared with many others the ‘Archimedes’ would stand much better.

This apparent superiority of the screw over the paddle as regards the resistance offered to it by the water may at first appear startling, but there is a great mistake committed in assuming that the action of the screw is a very oblique action, tending rather to drive the water laterally with a rotatory motion than to push it steadily backwards.

Having witnessed and carefully observed the degree and the nature of the disturbance in the water caused by the screw, and comparing this with the violent displacement of the water by the action of paddle-boards, even under the most favourable circumstances, I no longer feel surprised.

The mass of water pushed backwards by the action of the screw appears to be very large, spreading from the screw probably in the form of an inverted cone, but there is little or no appearance of any rotatory motion, and the surface of the water is not put into rapid motion as in the case of the paddlewheel, which may be observed to impart a considerable velocity to the water, probably for a small depth only, but over a very large space.

As regards the oblique action also, a great mistake appears to have been generally made, and very naturally made, by most persons when first considering the working of the screw. It is generally assumed that the inclined plane formed by the thread of the screw strikes the particles of water at that angle and with the velocity of the revolution of the screw, but it is forgotten that the screw is moving forward with the ship, and therefore that the angle at which the water is struck by the plane is diminished by all that much that the ship with the screw advances--indeed, it is evident that if the ship advanced the whole amount of the pitch of the screw, the screw, oblique as it appears, and rapidly as it revolves, would not strike the water at all, but simply glide through.

The angle at which any given part of the screw does in fact strike the water is only equal to the difference between the angle to which that part of the screw is formed and the angle or direction in which it moves by the compound motion of the revolution of the screw and of the forward motion of the ship and screw; and, contrary to one’s hastily imbibed notions of the action of the screw, this angle at which the plane of the screw is driven against the particles of water, is in such a screw as that of the ‘Archimedes’ very nearly equal over the greater portion of the surface, diminishing to nothing at the centre; and the motion imparted to the water, although perpendicular to the plane of the screw in point of direction, is small in extent or velocity, being also nearly the same over the whole surface of the screw, except close to the centre, where it is infinitely small.

In the ‘Archimedes’ screw, which appears to the eye so oblique, and the centre part of which would appear to act flat against the water, only causing it to revolve, the outer circumference being 18 feet and the slip 1 foot 8 inches, the angle at which this outer edge acts upon the water is only one in 11½.

The total amount of motion imparted to the water at right angles to the plane of the screw by one entire revolution even at the outer edge is not quite equal to the slip, being only 1·67 foot. The rotatory motion is still less, the total distance to which any particle of water is displaced laterally, or at right angles to the axis of the ship, by one entire revolution of the screw being at the outer edge only 0·69 foot, and the maximum distance being in any screw only equal to half the slip, and occurring at that part of the screw where the circumference is equal to the advance of the ship due to one revolution. This maximum of lateral motion is 0·9 foot, and takes place at 0·99 foot, or about 1 foot from the centre. In this mode of considering the direction at which the particles of water are acted upon by the plate of the screw I have taken no notice of the effect of the friction upon the surface of the screw, which, causing to be carried with it a film of water, will modify more or less according to the degree of smoothness of the surface the effect of the screw upon the water; and towards the centre this friction, however smooth the surface may be made, will gradually become equal to, and at last greater than, the propelling effect of that part of the screw; but this defect applies only to a very small portion of the whole area of the screw, and the absence of any very violent impulse to the water in a direction approaching to a right angle with the axis of the vessel, and which has always been assumed as an unavoidable evil in the screw, will account for the absence I have observed upon of any apparent rotatory motion.

I would not pretend, however, to advance these circumstances which I have observed, or these reasonings, as arguments whereon to found an opinion of the action of the screw, the facts as proved by the experiments are what I rely upon; but it is satisfactory to be able to account for the results by circumstances actually observed, and the reasons which suggest themselves.

The effect of a propelling surface in the form of a screw, and moving at a certain velocity, as compared with an equal surface moving at the same velocity but applied in the shape of paddle-boards, having been ascertained, it remains to determine the comparative power required to give motion to that surface.

The difficulty of determining this with any degree of accuracy from any experiments which we could make on board the ‘Archimedes’ was very great, but considering such results as I could obtain in conjunction with experiments which I have since made in our own works, and with the results upon steamboats recorded by others, and of those of experiments made by Colonel Beaufoy on the resistance of bodies in water, I think we may arrive at approximate conclusions sufficiently accurate for our purpose, and which may safely be relied upon.

In the case of the ‘Archimedes’ the engines were certainly not effective well-working engines, the proportions of the gearing or wheel-work between the engine and the screw was bad--such that the engine could not attain its proper speed--the friction of the gearing (which, whether it be a source of resistance necessarily attending the use of the screw or not, I shall consider afterwards) was very great, and the surface of the screw itself, which I had an opportunity of examining out of water, was so rough as necessarily to create very much more friction than would be caused by a tolerably smooth metallic surface. With all these sources of resistance, and under these unfavourable circumstances, the power calculated for the effective pressure on the piston and without deduction for friction or other causes, which, for the sake of distinction hereafter, I shall call the gross power, was about 145 horses, the speed of the vessel being about 8⅓ knots per hour, as actually measured by the land, and full 9 knots as measured with great care by heaving the common log, the midship section being, as before stated, 122 feet, and the lines of the vessel not so good as those of fast boats; comparing this with the gross power of the ‘Great Western’ engines when propelling that vessel at the same velocity, with the advantage of better lines and the other advantages arising from greater dimensions, there does not appear any such discrepancy as to indicate any loss of power by the use of the screw in the ‘Archimedes’; on the contrary, the power expended in the ‘Great Western’ is actually as great as that in the ‘Archimedes,’ as compared with their relative midship sections--and if any great allowance is to be made for the circumstances which I have referred to of larger dimensions and better lines, there would appear to be actually less power expended in proportion to the dimensions and form of the ‘Archimedes’ than in the ‘Great Western.’

The results obtained with the ‘Great Western,’ which as regards speed are similar to those of the ‘Archimedes,’ are necessarily taken from experiments made when she was rather deep, and the speed thereby reduced to 7·9 knots; but I have compared these with results reduced by calculations from experiments at higher speeds, and I find them agree satisfactorily--indeed, at the draft and consequent immersion of paddles when in this state, I consider the ‘Great Western’ as very nearly at her best as regards economy of power and effect produced. I should observe that the particular experiments from which the following calculations are deduced were made with the ‘Great Western’ in smooth water in the Severn. I have added also some calculations deduced from data given by Tredgold as to the performance of the ‘Ruby,’ a good boat with immense surface of paddle-board.

The comparison stands thus:

+--------------------------------------+---------+-----------+-----+ | | GREAT | | | | WESTERN | ARCHIMEDES| RUBY| +--------------------------------------+---------+-----------+-----+ |ACTUAL DIMENSIONS: | | | | | Midship section | 520 | 122 | 63 | | Area of board immersed | 230 | --- | 64 | | Area of a disc of diameter of screw | --- | 26 | -- | | | | | | |RELATIVE DIMENSIONS AND POWER: | | | | | Area of propelling surface, midship | | | | | section being = 1 | 0·442 | 0·213 |1·016| | Gross power expended for one | | | | | square foot of midship section | 1·023 | 1·026 |0·976| +--------------------------------------+---------+-----------+-----+-

The speed being the same, viz., 7·9 knots, the power expended is as nearly as possible the same in the three, and equal to one horse-power gross to one foot of midship section; while the relative propelling surface in the ‘Archimedes’ is equal to only half that of the ‘Great Western,’ and one-fifth that of the ‘Ruby.’ This _gross_ horse-power, it will be observed, is _about_ equal to one-half a nominal horse-power.

I have made several comparisons with recorded observations made on board the ‘Great Western’ at different times, and with experiments made in other vessels, and I find the same result; in estimating the powers used more particularly in some comparisons with the ‘Great Western,’ I have taken the mean pressure as ascertained on both sides of the piston, while in the ‘Archimedes’ I only obtained that on the top of the piston, which appears generally to be the best, and consequently the estimate is made unfavourably to the ‘Archimedes.’

Such general results are all that I could obtain from the experiments on board the ‘Archimedes,’ but since that time I have made some experiments upon the friction of a plate of metal in water, and have compared these results with the experiments of Colonel Beaufoy, and the conclusion I have come to is that the power absorbed by friction in a well-made screw, apart from all question of the means adopted for working it, would not be such as to interfere with its beneficial application.

The resistance created by the screw itself arises principally from two sources--the resistance to the cutting edge and the tail-edge, and the friction of the surface in contact with the water. The amount of the first may of course be reduced to an unlimited extent by having a fine edge, and practically such edge ought to be much finer than that of the screw of the ‘Archimedes.’

The friction upon the surface will of course materially depend upon the smoothness of that surface, and in the ‘Archimedes’ it was very rough, the iron being corroded at many places, with exfoliations and small holes--the corrosion arising apparently from the galvanic effect produced by the iron and the ship’s copper.

The great number of revolutions required in the screw as compared with those of the paddlewheel, leads a person to assume, without much consideration, that a very high velocity is given to the cutting edges and to the surface of the screw, and consequently that great friction must be produced--this velocity is not, however, nearly so great as it at first appears.

In the present screw of the ‘Archimedes’ the velocity of the extreme point, following its oblique or spiral course, is only about three times that of the vessel, while the average velocity of either of these knife edges or of the surface is not twice that of the vessel.

Now without determining what the actual amount of these resistances may be, we can at once satisfy ourselves that it cannot be very considerable, by comparing it (which we have the means of doing) with the resistance caused by the cutwater and any given portion of the ship’s bottom. The resistance of a knife-edge will be about as the square of the velocity, and if we assume the surface friction to increase in the ratio determined by Colonel Beaufoy--namely, at the 1·75th power, or as the 4th root of the 7th power of the velocity--then the resistance of the knife-edge will be equal to the resistance of a similar edge of about five and a-half times the length of the diameter of the screw moving at the same rate as the vessel, and the surface friction will be equal to that of a piece of the ship’s bottom about six and five-eighth times the area of the screw--or, in the case of the ‘Archimedes,’ the additional power absorbed by the friction of the screw would be about equal to that absorbed by the friction of little more than twice the space of the dead wood which had been cut out to receive the screw--while the knife-edges would be about equivalent to three knife-edges immersed in the water, of the same depth as the ship’s stem.

The actual amount of power absorbed in driving the ‘Archimedes’ screw was probably about twenty horse-power gross, or from ten to twelve nominal horse-power; but I have no doubt that a screw of similar diameter and in good condition would not absorb half that power: and this amount may be still further, and very much reduced, by increasing the relative size of the screw to that of the ship, and thereby reducing the slip, and proportionately reducing the number of revolutions required.

The great extent to which this is capable of being carried will at once be seen when I state that if the ship’s progress were made to be 7 feet instead of 6 feet to each revolution of the screw, which a very slight increase of diameter and pitch of screw would effect, the power absorbed in driving the screw would be diminished in the ratio of the

6^{2}^{4} √6^{7} to 7^{2}^{4} √7^{7}--that is, as 6-15/4 to 7-15/4, or about as 3 to 2.

I must repeat here the observation I have previously made, and remind you that these calculations are not introduced as _proving_, but merely as _explaining_, that which appears to me proved by the general results of the experiments on the ‘Archimedes’--namely, that the effect produced was, considering all the circumstances, fully proportionate to the power expended, while the experiments and calculations which I have since made also satisfy me that these results may be very much improved upon.

As regards the first of the two heads under which I stated that I proposed to consider the subject, namely, the mere efficiency of the screw as a propeller, I think but one conclusion can be drawn from the results of the experiments quoted, and that is, that as compared with the ordinary paddlewheel of sea-going steamers, the screw is, both as regards the effect produced, and the proportionate power required to obtain that effect, an efficient propeller.

I limit the comparison to the ordinary paddlewheels of sea-going steamers, first, because those are the circumstances which _we_ have alone to consider; and, secondly, because it is _possible_, by increasing the diameter and breadth of the paddles, which, for the attainment of an adequate object is practicable to any extent in a mere river boat, to render the action of the common paddle all but perfect, and probably more effective than any other propeller.

In considering the advantages and disadvantages likely to attend the use of the screw propeller, I will, commencing with the latter, consider such objections as have been advanced by others, as well as those which may have occurred to myself.

The only objections, however, which I think worth consideration are:--

First. The necessity of a peculiar form of vessel.

Secondly. The situation of the screw under water, and consequently to a certain extent unseen and inaccessible, and the liability to injury from its position from grounding or in other ways.

Thirdly. The probability of its being lifted out of water when the ship pitched deep.

Fourthly. The difficulty of getting up the required number of revolutions, and the great defects of the mode employed in the ‘Archimedes,’ and the shaking caused by the machinery.

As regards the form of vessel, undoubtedly a shallow boat, intended for shallow waters, would be very unfit for the application of the screw, which would probably require a greater depth of water than the whole draft of the vessel; but I see no defect or difficulty of this description in the vessel now under consideration, nor can I anticipate any in any vessel this Company is likely to be interested in; a clean run is the most essential condition, and I should suppose no ship was ever built in which this principle of form was carried to a greater extent than in our new iron ship. Her present form I believe to be excellent for the screw, and with a very slight dropping of the keel towards the stern, which can easily be done now without any expense, assisted by the different trim, which, as I shall presently show, will be effected by the use of the screw, the required draft of water will be attained.

It may, perhaps, be as well to mention here, that the diameter of the screw, if in the same ratio to the midship section as in the ‘Archimedes,’ would be only 12 feet 3 inches, my friend Captain Claxton having made a mistake upon this point in calculating it at 16 feet, and that if increased only to 14 feet 4 inches, the diminution referred to in a former part of my Report of one-third in the power lost in working the screw would be effected; considering the speed we wish to attain, probably 15 feet 6 inches would be a good diameter. Upon the whole I think the vessel is as well fitted for a screw as she is for paddles, and much better adapted for either than the ‘Archimedes;’ but if originally intended for a screw, possibly some trifling modification in the form and construction, principally of the keel near the stern, might have been introduced which would have rendered the whole a more perfect job than she would now be if altered--but the absence of this would in no way lessen the efficiency of the screw, and I cannot think that any alteration we might now be obliged to make would exceed in cost the sum of 200_l_.

Secondly, the inaccessibility of the screw and liability to damage; this appears to me the objection most plausible, but I cannot say that I attach much weight to it, particularly in the case of a vessel intended for long voyages and across the ocean. During the whole passage in deep water I consider the screw far less exposed to injury than a paddlewheel, and that the chances of injury are so remote that even if it were quite inaccessible it would still be altogether safer than paddles, which are so much exposed; but it is by no means inaccessible, the screw may be rendered stationary at any time or during any weather, when it would be barely safe to stop the engines with common paddles, and when it would be very difficult to do anything to the paddles even if the engines were stopped, while the whole of the screw, bearings, &c., may easily be examined and felt from above, and, if necessary, men sent down with common diving jackets and hoods to replace bearings, or attach tackle to move the screw, or clear away any obstacle entangled in it. When in port I still think the chances of injury very remote; an inspection of our model will satisfy you that from the form and size of her midship section the vessel cannot lay in any position in which the screw would touch the ground, while at that time the whole screw may be very easily examined and replaced without any necessity for going into dock.

Thirdly, the probability of its being lifted out of water when the ship pitches deep.

This appears at first to be a very natural and an unavoidable objection, but the result of observations proves that the motion of vessels, of steamers at least, is not such as to cause the apprehended difficulty. Among the observations made on board the ‘Great Western’ steam-ship by Mr. Berkeley Claxton, under my direction, were measurements of the angles of rolling and pitching, and from these it was evident that the vessel never pitches to so great an angle as that to which she rises; such a result might indeed have been anticipated by considering the form of the vessel forward and aft, and the circumstance that a steamer is almost invariably meeting or passing the seas, or, if overtaken by them, is still going at a good rate, which reduces the relative speed of the sea; consequently, although the vessel may be frequently thrown up very violently forward, yet the stern, which has no displacement under water, settles down quietly and heavily upon the surface; or, considering it in another way, the variation of displacement at the stern is very rapid, falling off almost to nothing at a few feet below the water-line, and spreading out to a great extent at a few feet above, whilst forward the difference of displacement is comparatively small, the centre of motion, therefore, is thrown very far aft, and while the bows, which are also opposed to the first shock, are thrown alternately high out of water or plunged deeply into it, the stern floats nearly steady, the vessel resting on its broad counter nearly as the centre of motion: whatever may be the explanation such is the operation, not only as measured by instruments, but more particularly as observed since, practically.

In the ‘Great Western’ the whole cutwater and, it is said, a considerable length of keel, is frequently seen out of water from the bowsprit, while astern it is very doubtful whether more than half the stern part was ever seen; marks have been made by my direction on the rudder to observe this; as yet the 9-foot mark is the lowest seen, and this occurring rarely, and for very short intervals.

In the ‘Archimedes,’ during a voyage performed in her by Mr. Guppy from Bristol to Liverpool, and during which they were exposed on more than one occasion to violent pitching, the screw (which can be watched from the deck) never was uncovered; and Mr. Smith and others on board the ‘Archimedes,’ whose whole conduct was such as to inspire unusual confidence in all information obtained from them, assured me that such was always the case.

In the voyage to Oporto and back, in which I sent Mr. Berkeley Claxton, he made the same observation; these facts, in conjunction with previous and subsequent observations on board the ‘Great Western,’ convince me that nothing is to be feared on this head; but even if the screw were occasionally to be partly exposed, I know of no evil consequences likely to ensue, as I shall clearly point out when referring to the _advantages_ of this propeller over the common paddle.

Fourthly, the difficulty of getting up the required number of revolutions, and the great defects of the mode employed in the ‘Archimedes.’

Upon this point certainly the ‘Archimedes’ offers but a miserable example, and the result is almost enough to prejudice the mind of any person against the whole scheme; the proportions of the gearing, as I have before stated, are so bad that the engines appear, even to the eye, to labour ineffectually to get up their speed. The required speed of the screw is not nearly attained, while the noise and tremor caused by the machinery is such as to render the vessel uninhabitable, and perfectly unfit for passengers, I should almost say for a crew. I never attached much importance to these circumstances, because I felt convinced that such a mere mechanical difficulty would by some means be overcome, if, as I confess I did not then at all anticipate, the screw itself should prove efficient.

The most simple and effectual means of overcoming all objections on these heads always appeared to me to be by the use of straps instead of gearing; and all my experience, and I have seen a great deal of the working of machinery by straps and ropes in the numerous works executed by my father, led me to the conclusion that there existed no difficulty whatever in sending the necessary power through a rope or hemp strap, but I was hardly prepared to find the result so entirely satisfactory as it has proved to be.

In an experiment made in your works at the yard, I have sent through two small whale lines, a power equal to about one-thirtieth of that which would be required in the strap if used in the new ship, and this without any slip or straining of the rope which would be injurious in practice, and without any peculiar means of ensuring adhesion to the drums; so that we have ascertained beyond doubt that sixty such whale lines upon a drum of only 4 feet 3 inches diameter is adequate to our wants, but if we suppose seventy lines of superior manufacture to that used in the experiments with a perfect mode of tightening and working upon a drum of 6 feet diameter, all of which can easily be had, it will ensure the perfect and easy working of a mode of obtaining the required number of revolutions of the screw without noise or tremor. The strap in question would be only about 3 feet or 3 feet 3 inches broad, easily replaced piecemeal, and even, if necessary, without stopping the engines.

All the difficulties enumerated under the fifth head may be considered as entirely overcome, or rather as ceasing to exist; and so far from the working of the screw involving difficulties and unavoidable friction, noise, or tremor, it may be worked with unquestionable and perfect facility, and as compared even with the best-made paddles in smooth water, the whole machine will be noiseless.

It is almost unnecessary that I should say that the screw, apart from the gearing in use on board the ‘Archimedes,’ _cannot_ and _does not_ produce the slightest tremor or noise--it was with some difficulty, and at least only by attentively listening, that the revolutions of the screw could be counted, even when disconnected and free from the noise of the engine or gearing and the vessel being towed, and then only from some defect in the bearings or the shaft of the screw causing a slight beat.

In thus answering the objections supposed to have been urged against the use of the screw, I may probably have appeared to see everything in a favourable light; unhesitatingly I admit that it is so, and that both formerly when I was completely sceptical as to the mere efficiency of the screw as a propeller, and since my doubts on that head have been removed, I always felt that upon all other points the screw possessed every superiority that could be desired over a common paddlewheel for a sea-going vessel.

I shall now proceed to point out the principal advantages peculiar to the use of the screw; they are--

First. A considerable saving of weight, and that principally top weight.

Secondly. The admitting of a better and simpler form of vessel, having greater stiffness with the same quantity of material, and offering less resistance to head wind and seas, and affording more available space within.

Thirdly. The operation of the screw being unaffected by the trim or the rolling of the vessel, and allowing of the free use of sails, with the capability of entirely disconnecting the screw or of varying the multiplying motion so as to adapt the power of the engine to the circumstance either of strong adverse winds or scudding.

Fourthly. Perfect regularity of motion and freedom from the possibility of violent shocks to the engines.

Fifthly. The singularly increased power of steering given to the vessel--and

Sixthly. The great reduction in the breadth of beam.

I have gone into some detail in calculating the weights of the parts which are not common to the two systems, and I find that the difference, or actual diminution in weight in favour of the screw as applied to our new ship, is upwards of ninety-five tons; but that a much greater weight even than this is transposed from the top of the ship to the bottom--no less a mass than one hundred and sixty tons is removed from the level of the paddle-shaft or from about 10 feet above the water-line, and replaced by sixty-five tons at about 7 feet below the water-line; not only is buoyancy, and consequently proportionate space for cargo, gained to the extent of the difference, but the relief to the labouring of the vessel in bad weather from the change of position must be immense. If the reverse were under consideration, if in a vessel fitted for sea, however stiff in trim or form, it were suggested to remove sixty-five tons of her ballast, and to place one hundred and sixty tons upon her deck, and thus navigate her across the Atlantic in all weathers, it would probably be considered, not merely as highly dangerous, but as actually impossible. Although such an opinion as that it would be impracticable we now know would be incorrect, yet the extent of the beneficial change is much more striking when considered in this way. As regards the trim of the ship, about one hundred and forty-five tons would be removed from nearly the centre of flotation, and the balance of fifty tons added and distributed over the after part, principally quite aft.

I have not calculated the exact effect of this upon her trim; it would only bring her down by the stern, and this is a defect which there seems, as we too well know, never any difficulty in remedying.

Secondly. The simplifying and improving the form of the ship--both as regards strength and mass exposed to the wind and sea.

The necessity of contracting the midships of a steamer, and making her completely wall-sided, and forming a sort of recess to receive the paddles, interferes considerably with the framing of the ship. In a wooden ship of the size of our new one the whole beam of the ship would have to be contracted in order to carry the planking through in a direct line and obtain the requisite fore and aft tie as has been done in the ‘Great Western’; in the new ship the almost infinite resources afforded by the material used, enabled us to expand the sides and obtain breadth of beam for cabin room, both before and abaft the paddles, and contract the sides at the paddles as seen upon the plan; but in order to strengthen this part, so evidently weak by form, much contrivance and much material was required. By dispensing with paddles, the best form of ship is left free to be adopted; perfect lines may be preserved, more equal strength obtained with increased space, and the whole mass of paddle-boxes and their accompanying sponsons and deck-houses swept away, and the resistance of these huge wings to head winds or seas entirely avoided.

The space gained by avoiding the contraction is calculated by Mr. Patterson to amount to two hundred tons measurement; this would be entirely gained, and would not even involve increased dues or tolls, as it would be added to the engine-room; it would therefore perhaps counterbalance any loss of room caused by the shaft conveying the movement from the engine to the screw, but I believe this nominal increase at one part would not be so great, while in fact the ship would really be more compact, and, though to a very small extent, a smaller ship, as the sponsons would be removed.

The third point of advantage named is perhaps the most important. With paddles, the action is materially affected by the depth of immersion; when the vessel is deep, and consequently the paddles deep, their action is impeded, a greater part of the power of the engine is absorbed in driving the paddle, the speed of the engine is reduced and the effect diminished; when too light also the paddles do not take sufficient hold of the water, the amount of slip increases and power is wasted; in rolling the same effects are produced, and thus at those times when the greatest effect is required, namely, with deep immersion or in bad weather to overcome the increased resistance offered to the vessel, the propelling power is least effective, and Captain Hoskins actually estimates this loss as occasionally equal to two-thirds the whole power.

The bad effects of one paddle being immersed too deeply, and the other not sufficiently, also prevents the free use of the sails; and it must often occur that the impediment thus offered to the working of the paddles more than counterbalances the good effects of a tolerably fair wind. With the screw the effect is constant, at least unaffected by the position or motion of the ship, whether deep or light the screw acts nearly the same, and as to rolling or heeling over, the screw would work equally well (as long as it be immersed) if the vessel were on her beam-ends or bottom upwards.

The screw therefore leaves the ship free to be used as a sailing-vessel to any extent that other circumstances will admit of, and as long as the sails draw there can generally be no doubt that the wind is assisting the ship. The screw may also be thrown in and out of gear at any time and during any weather, either in case of accident to the engines, or in the event of her scudding before a gale of wind, when the engine would be useless; this last, however, I do not consider a probable occurrence, particularly if another arrangement of which the screw is susceptible be taken advantage of.

If the motion be conveyed by a strap, as I have recommended, there is no difficulty in having two or even three drums on the screw-shaft of different diameters, and thus when the resistance to the ship is very much increased by strong head winds, deep draught, and other causes, to use the slow motion and obtain an increased propelling force, or when, on the contrary, the vessel is running before the wind to use the quick motion--by which, in both cases, a great increase of speed would be attained.

This is in fact obtaining at once and by simple means all those advantages, and to a much fuller extent, which are aimed at in the reefing-paddles.

Fourthly, great regularity of motion is naturally consequent upon the screw being unaffected by the rolling of the ship, and upon its being immersed and not exposed therefore to blows from the sea, and except in the case of its being lifted out of water, the resistance is perfectly uniform and perfectly smooth.

An engine could not have a work less capable of causing any jar or shock as to the effect; even if lifted partially out of water the variation of resistance would be as easy or soft, to use a mechanical term, as possible, while the extent of the variation could never approach to that to which paddles continually expose an engine. A heavy sea or a deep plunge will occasionally bring the engines nearly to a stand; while at other moments, if the engineers are to be believed, the paddles are left free and the engines run away at a fearful speed. I am inclined to think this description of the effects somewhat exaggerated; but certainly the screw cannot by possibility be exposed to the same variations as the paddles--it cannot be stopped by the action of the sea, indeed, being wholly immersed, the resistance cannot be increased at all, while under no circumstances can it be relieved to the extent to which paddles are, which may both on some rare occasions be quite out of the water; and therefore whether the resistance of the screw is so constant as I believe it to be, or not, yet as compared with that offered by paddles, it is certainly all but perfectly constant.

Fifthly, the effect upon the steerage is singular, the mass of water put into motion by the thrust of the screw is thrown directly upon the rudder, and the consequence is not only that when the ship is going at any given rate, the rudder is passing through the water at a greater rate, and consequently is more sensible, and acts more powerfully upon the ship; but even when the ship has no way, but the screw is at work, the rudder is acted upon by water moving perhaps at two or three knots per hour, and the vessel is still under command--this must be a most important power to possess in a ship, and must materially diminish many of the greatest dangers arising from a strong head wind and sea, and at the same time and under the same circumstances must increase the speed by improving the steerage.

And lastly, her diminished breadth of beam. Important as this alteration would be to any vessel, it is peculiarly so as connected with Bristol; the total breadth, including paddle-boxes, would be at least 78 feet; with the screw, and taking all the increased beam that might be convenient, it would be under 50--very nearly 30 feet of difference. One of the principal objections to her coming up the river would be removed, and the dock gates might easily be made to receive her.[201]

There are many other points upon which comparisons may be drawn, but I am not aware that any very important differences exist.

As regards first cost I believe there would be little difference--if any, it would be in favour of the screw; as a reduction of ninety-five tons of iron can hardly fail to cause some saving, although some portion of the substituted machinery may be more costly per ton.

As regards wear and tear I can have no doubt that some considerable saving would be effected; the paddles are a constant source of trouble and expense, and seem never to be capable of being kept in good repair; indeed, they are huge and comparatively light frameworks subjected to extraordinary and constantly repeated shocks, each arm receiving direct about 260,000 very sharp blows per voyage, independently of the more violent shocks from heavy seas, while the screw can be subjected to no such constant source of mischief.

From all that I have said it must be evident to you, gentlemen, that my opinion is strong and decided in favour of the advantage of employing the screw in the new ship; it certainly is so. I am fully aware of the responsibility I take upon myself by giving this advice, I am also fully sensible of the large amount we have at stake, and I have not forgotten the nature and tone of the observations which have on more occasions than one been so freely made by individuals upon the course we have hitherto pursued; although, and I have pleasure in referring to the fact, this course has in every instance where results have been obtained proved successful; but my conviction of the wisdom, I may almost say the necessity, of our adopting the improvement I now recommend is too strong, and I feel it is too well founded, for me to hesitate or to shrink from the responsibility.

I think I have hardly advanced an opinion which I have not supported, and in most cases preceded, by a statement of facts, leaving no doubt as to the correctness and safety of relying on these opinions; still it would be too much to hope that my mode of laying before you these facts which I have collected and the opinions I have formed could produce as strong a conviction in your minds as the consideration of them has in my own; but if you bear in mind that the actual results of the fair and full trial of the ‘Archimedes’ for several months has completely established the fact of the efficiency of the screw as a propeller; that the experiments I have made, as well as the general and apparent results of her working, have equally satisfactorily explained the fact of the power required being no greater in proportion to the effect produced than in the ‘Great Western’ steam-ship, and many other good steamboats; and that these results are satisfactorily explained by theory, you cannot fail to draw the same conclusion that I have done as to the general question of at least the equal efficiency of the screw.

As to the comparisons I have drawn between the general and what I may call the indirect advantages of the one mode of propelling over the other, they seem to me so evident that I am disposed to apologise to you for having occupied your time in pointing them out, and we have the satisfaction of knowing that they are now very generally admitted, particularly by practical men.

In conclusion, I must observe that much more detailed information and recorded results than appear on the face of this Report have been required to enable me to form correct comparisons, and to reduce to calculation and to actual figures and amounts many results observed; and that it would have been impossible for me to have given you such clear and positive facts on many most important points without the very detailed observations made and recorded by Mr. Berkeley Claxton in the several voyages of the ‘Great Western,’ and also in one on board the ‘Archimedes.’

The information obtained from these logs has been, and may still be, of the greatest importance to us in our future working, and I have much pleasure in adding that the manner in which my directions were carried out was highly creditable to Mr. Berkeley Claxton, who, I think, has conferred a great benefit on the Company by his labours. I have to express also my thanks to my friends Captain Claxton and Mr. Guppy for their assistance in the various experiments which have been made, and in working out the results.

I am, Gentlemen,

Yours very faithfully,

(Signed) I. K. BRUNEL.

INDEX

‘Adelaide’ steam-ship, built under Mr. Brunel’s directions, 290

Admiralty, Mr. Brunel’s connection with the, respecting the screw propeller, 283. Communication with the, on floating gun-carriage, 459

Airy, G. B., Astronomer Royal, member of the Gauge Commission, 117. Correspondence with Mr. Brunel on astronomical observations for the ‘Great Eastern,’ 321

Angarrack, viaduct at, 189

‘Archimedes’ steamer, the screw propeller used in the, 253. Experiments made in the, 254

Armstrong, Sir W. G. His hydraulic machinery at Paddington station, 85 _note_.^{1} Engaged with Mr. Brunel on gunnery investigations, 452. Letter to, 454, 461

Atlantic cable expeditions of the ‘Great Eastern,’ 412. Loss of the first cable, 412. A second one laid, and the first recovered, 413. The French cable of 1869, 413

Atmospheric system of propulsion on railways, 131. Description of this method of traction, 134. History of its introduction prior to 1844, 136. Mr. Brunel’s views respecting it, 137. His report recommending its adoption on the South Devon Railway, 138. Grounds of his recommendation, 142. Select Committee on, 144. Working of the system, 153. Imperfections of engines, 154, and longitudinal valve, 157. Mr. Brunel’s report on the failure of the Atmospheric apparatus, 159. Abandonment of the system, 164

Australian Mail Company, Mr. Brunel appointed engineer of the, 290

Barlow, Professor P., member of the Gauge Commission, 117

Barlow, W. H., 57

Bath, station at, 84

Bath, bridges at, 175, 179

Bathford, bridge at, 175

Beamish, Richard, his account of Sir Isambard Brunel’s block machinery at Portsmouth, quoted, 3. Joins the Thames Tunnel works, 21

Bennett, Joseph, Mr. Brunel’s secretary, 92

Berks and Hants Railway, 88

Birmingham and Oxford Junction Railway, 90

Birmingham, Great Western extension to, 124

Birth of Mr. Brunel, 1

Blake, H. W., consulted by Mr. Brunel on the ‘Great Eastern,’ 297

Block machinery at Portsmouth, Sir Isambard Brunel’s, 2

Bourbon, Ile de, Sir Isambard Brunel’s suspension bridges for the, 5. Description of them, 40

Bourne viaduct, 181

Box Tunnel, 70 _note_^{1}, 72, 81. Criticism as to its safety, 81. Letter from Mr. Brunel on the, 81

Bremner, A., 263, 280

Brentford, dock at, 440

Brentford, extension of the Great Western Railway to, 86

Brereton, Robert Pearson, chief of Mr. Brunel’s engineering staff, 92, 210, 215 _note_^{1}, 217 _note_^{1}, 223, 225, 437, 438 _note_^{1}

Brickwork, use of, 59. Bridges in, 172

Bridges, suspension, Sir Isambard Brunel’s: in the Ile de Bourbon, 5, 40; designs for the Serpentine, and for the Thames at Kingston, 5. Mr. Brunel’s: at Clifton, 46; Charing Cross, 59

Bridges, railway, 171. 1. Brickwork and masonry bridges, 172. Flying bridges, 176. Skew bridges, 177. Letter from Mr. Brunel on bridge construction, 178. 2. Timber bridges and viaducts, 179. 3. Cast-iron bridges, 190. 4. Wrought-iron bridges, 192. Girder bridges, 193. Opening bridges, 195. Trussed bridges, 199. Extracts from letters on bridges of large span, 212 _note_^{1}. Experiments on matters connected with bridge construction, 227

Bristol, Mr. Brunel’s early connection with, 58, 64. Station at, 84. Bridges at, 175, 195. Floating Harbour, 422. Proposed improvement of the port, 426. New lock at, 427

Bristol and Exeter Railway, 86

Bristol and Gloucester Railway, 90

Bristol and South Wales Union Railway, 90

Briton Ferry Docks, 437

Broad Gauge. _See_ Gauge

Brunel, Sir Marc Isambard, birth of, 2. Arrives in England, 2. Marries Miss Sophia Kingdom, 2. Designs the Block machinery at Portsmouth, 2. Veneering machinery, 5. Shoe machinery, 5. Designs suspension bridges for the Ile de Bourbon, 5, 40. Experiments on carbonic acid gas, 5, 42. Proposes the Thames Tunnel, 5. Extracts from his Journal relating to the Rotherhithe shaft, 10. Extracts from his Journal relating to the works at the Thames Tunnel up to January 1828, 16. His death, 39. Hoop iron introduced by, in brickwork, 177. Designed a large timber bridge to cross the Neva, 211 _note_^{2}

Bullo Pill opening bridge, 197

Caermarthen, opening bridge at, 198

Carbonic acid gas, experiments on, by Sir Isambard Brunel and Mr. Brunel, 5, 42

Cast-iron bridges, 190. Mr. Brunel’s views as to the use of cast iron in bridge construction, 190, 192

Cheltenham and Great Western Union Railway, 88

Chepstow bridge, 203. Mode of forming piers, 203. Description of superstructure, 206. Floating and erection, 209

Clarke, Seymour, 117

Claxton, Captain, 57. Assists Mr. Brunel at the floating of the Chepstow bridge, 210. And the Saltash bridge, 222. Appointed Managing Director of the Great Western Steam-Ship Company, 234, 242, 247. Letter to, from Mr. Brunel, on the ‘Great Britain,’ 264. Goes to Dundrum to carry out Mr. Brunel’s plans for the protection of the ‘Great Britain,’ 272. Letter to, from Mr. Brunel, on the breakwater, 272. Report of, on breakwater, 274. Superintends floating of the ‘Great Britain,’ 280. Consulted by Mr. Brunel on the ‘Great Eastern,’ 291, 297. Floating Harbour, Bristol, 424

Clifton Suspension Bridge, origin of the, 47. Mr. Brunel’s designs, 47. Rejected by Mr. Telford, 51. Mr. Telford’s own design, 52. Second competition, 52. Mr. Brunel successful, and appointed engineer, 53. The site described, 54. Description of the design, 55. Architectural features, 56. Commencement of the work, 56. Completed, 57

Coles, Captain Cowper, 461

Construction of works, letter on, 178

Continuous girders, 208

Cork and Youghal Railway, 91

Cornwall Railway, 87. Viaducts on, 185

Crystal Palace at Sydenham, water-towers of the, 448

Cylinders, of Chepstow bridge, method of sinking the, 204. The great cylinder of the Royal Albert Bridge, 214

Dalkey Railway, Atmospheric System on, 131

Dartmouth and Torbay Railway, 87

Death of Mr. Brunel, 520

Dock and pier works: Monkwearmouth, 418; Bristol, 422; Plymouth, 433; Briton Ferry, 437; Brentford, 440; Neyland, 443

Draught, Mr. Brunel’s paper on, 101 _note_^{1}

Dublin, railway to Wicklow from, 91

Dundrum Bay, stranding of the ‘Great Britain’ in, 263

Early life of Mr. Brunel. He goes to school at Chelsea, 4; at Brighton, 4; at Paris, 5. Employed in his father’s office, 5. Engaged at the Thames Tunnel, 6. References by Sir I. Brunel to his exertions, 17, 19, 21, 22, 25, 33. Appointed resident engineer, 25 _note_^{1}. First irruption of the river, 29. Second irruption, 35. Accident, 36. Visit to Plymouth, 46

Eastern Bengal Railway, 91, 195, 517

Eastern Counties Railway, gauge adopted on the, 105

Eastern Steam Navigation Company, formation of the, 291. _See_ ‘Great Eastern’

Egypt, visit to, 517

Electric telegraph, application of the, in connection with railways, 155

Engineer, Mr. Brunel’s view of the position of, 475. Of joint-engineer, 476. Of consulting engineer, 477. Of the position of the engineer in relation to the contractors, 477. To the Directors, 478. Remarks on interference of Directors with assistant engineers, 481. On State control over engineering works, 486

Experiments: Strength of timber, 182, 227. Cast-iron girders, 190, 191. Wrought-iron girder, 193. Riveting, 194, 228. Continuous beams, 209, 229. Bridge construction, 227. Ropes and chains, 228. Friction, 348, 368, 385

Faraday, M., his experiments on the liquefaction of gases, 42. Consulted by Mr. Brunel on the Kyanising process, 189

Field, Cyrus, 411, 414

Field, J., consulted by Mr. Brunel on the ‘Great Eastern,’ 297

Floating gun-carriage, 454

Floating harbour at Bristol, 422

Floating pier, proposed at Portishead, 426. In Mill Bay, 436

Florence and Pistoja Railway, 91

Flying bridges, 176

Ford, Captain Robert, consulted by Mr. Brunel on the ‘Great Eastern,’ 297

Friction, experiments and observations on, 348, 368, 385

Froude, W., letter to, describing floating of the ‘Great Eastern,’ 389

Gathampton, bridge at, 174

Genoa, Novi, and Alessandria Railway, 91

Gauge of railways, difference between the broad and narrow, 99. Origin of the ordinary gauge, 99. Adoption of the broad gauge on the Great Western Railway, 101, 106. Reasons for its adoption, 102. Attacks on, 106. Reports of Mr. Wood and Mr. Hawkshaw on, 107. Report by Mr. Brunel on, 107. Northern extension, 116. Inconveniences of a break of gauge, 116. Royal Commission on the gauge question, 117. Report of the Commissioners, 117. ‘Observations on the Report,’ 119. Report of the Board of Trade, 122. Act for regulating gauge, 122. The mixed gauge, 124. Summary of the advantages of the broad gauge, 127. Partial abandonment of the broad gauge, 127, 129. Report on the broad gauge, 525

Gilbert, Davies, appointed referee in the second competition for the Clifton Suspension Bridge, 52. Recommends Mr. Brunel’s design, 53

Girder bridges, 193

Glennie, W., 215 _note_^{1}

Gloucester, opening bridges near, 196

Gloucester and Dean Forest Railway, 88

Gooch, Sir Daniel, 117, 119. Experiments by, 125

Gravatt, William, an assistant engineer at the Thames Tunnel, 26

‘Great Britain’ steam-ship, commencement of the, 247. Report on the engines, 249. Adoption of the screw propeller, 254. Principal features of her design, 255. Arrives in the Thames, 261. Her voyages, 262. Stranded in Dundrum Bay, 263. Letter from Mr. Brunel on the subject, 264. His reports to the Directors, 267, 273. Construction of breakwater, 274. Floating of the ship, 280. Her subsequent history, 282. Dimensions of ship and engines, 282

‘Great Eastern’ steam-ship, origin of the project, 291. Memorandum by Mr. Brunel to the Directors of the Eastern Steam Navigation Company, 292. He is appointed engineer, 293. Letter on the form and dimensions of the ship, 294. Report on mode of proceeding, 296. On enquiries relating to the draught and form of the vessel, 297. On the dimensions, 299. Tenders invited, 300. Report on tenders, 301. Commencement of the work, 304. Extracts from Mr. Brunel’s memoranda, 304, 310. Letters on his position as engineer, 311. Report describing the ship, 315. Letter to the Astronomer Royal, 321. The observers’ department in the ship, 322. Captain Harrison appointed to the command, 323. Memorandum on the management of the ship, 324. Letter on the duties of chief engineer, 335. Suspension and resumption of the works, 339. Reasons for launching the ship broadside to the river, 340. Adoption of iron sliding-surfaces, 343. The ways and cradles, 345. Motive power, 348. Checking gear, 351. River tackle, 352. Letter to Captain Harrison on the river tackle, 354. Letter to the Directors respecting the operation of launching, 355. Memorandum of arrangements and intended mode of proceeding, 356. Particular instructions, 358. Final preparations, 359. Commencement of the launch, 360. Accident at one of the drums, 361. Failure of the first attempt, 362. Second attempt, 364. Report on operations, 366. Progress of the launch, 368. Suspension of operations, 376. Report and memorandum, 377. Re-commencement, 379. Floating of the ship, 382. Experiments and observations on friction, 385. Letter to Mr. W. Froude, describing the floating, 389. Formation of the Great Ship Company, 393. Progress of the works to Mr. Brunel’s last illness, 393. Completion of the ship, 393. Voyage to Weymouth, 393. Explosion of water-heater, 393. Storm at Holyhead, 395. Description of the ship, 396. Her first voyages to New York, 403. To Quebec, with troops, 404. Accident to rudder, and loss of paddlewheels, 405. Voyages in 1862, 407. Accident off Montauk Point, 407. Formation of Great Eastern Steam-Ship Company, 409. Remarks on performance of ship, 409. Employed in laying Atlantic cables, 412. The Indian cable, 414. Dimensions of ship and engines, 416

Great Exhibition of 1851, Mr. Brunel’s opinion respecting prizes to exhibitors, 445. His part in the work of the Building Committee, 446. Supports Sir Joseph Paxton’s design, 447

Great Western Hotel, 86

Great Western Railway, origin of the, 63. Mr. Brunel appointed engineer, 64. Survey of the country, 65. Bill for a line from London to Reading, and Bath to Bristol, read a second time, and referred to a committee, 66. Opposition to the Bill, 67. Plan of entering London, 68. Mr. Brunel’s cross-examination, 69. The Bill passed by the Commons, but thrown out in the Lords, 70. A Bill for the whole line introduced, read a second time, and committed, 71. Evidence taken before the Commons’ Committee, 72. Evidence before the Lords’ Committee, 73. The Bill receives the Royal Assent, 74. Construction of the line, 80. Opening from London to Bristol, 80. Levels and inclines, 80, 104. The Box Tunnel, 81. The Bath and Bristol stations, 84. Paddington station, 84. Branches and extensions of the railway, 86, 88, 90. Adoption of the broad gauge, 106. The permanent way, 108, 111. Meeting of shareholders on broad gauge, 111. Extension of the Great Western system, 116

‘Great Western’ steam-ship, formation of the company, 233. Details of the construction of the vessel, 234 _note_^{2}. Report on the selection of the builders of the engines, 235. Controversy with Dr. Lardner, 237. Launch of the vessel, and voyage to London, 241. Return to Bristol, 242. Fire on board, and accident to Mr. Brunel, 242. First voyage to New York, 243. Subsequent history, 244. Dimensions of ship and engines, 245

Gunnery experiments, 452

Guppy, T. R., 148, 233, 234, 247, 253, 254. Letter to, on iron-ship building, 259

Hammond, J. W., 65, 92

Hanwell, bridge at, destroyed by fire, 190

Hanwell viaduct, 172

Harrison, Captain, 223. Appointed commander of the ‘Great Eastern,’ 323. Letter to, on the river tackle, 354. At the launch, 362, 370, 382, 392

Haverfordwest, opening bridge at, 198

Hawkshaw, J., 57. Report on broad gauge and permanent way, 107

Henley branch of the Great Western Railway, 86

Hungerford Suspension Bridge, 57, 59

India, railway works in, 91

Indian Cable expedition of the ‘Great Eastern,’ 414

Institution of Civil Engineers, 516 _note_^{2}, 521

Inventors, communications with, 485

Ireland, railway works in, 90

Italy, Mr. Brunel’s railway works in, 91, 510

Ivybridge viaduct, 182

Kennet, bridge over the river, 175

Kidwelly, opening bridge at, 198

Kyanising process, 189, 421

Landore, viaduct at, 183

Lane, Michael, 29

Lardner, Dr., 114 _note_^{1}. Opinions respecting ocean steam navigation, 237

Llansamlet, flying arches near, 176

Llynvi Valley Railway, 89

Locke, Joseph, 62, 74. His address on the death of Mr. Brunel, 521

Locomotive power, comparison of, with stationary power, 142, 166

Loughor, opening bridge at, 197

Maidenhead bridge, 96, 173

Masonry, bridges in, 172

Maudslay and Field, 15, 148, 236, 284

Milford Haven, 88, 443

Monkwearmouth, docks at, 417, 418

Moulsford, bridge at, 174

Nasmyth, James, his steam hammer designed, 252 _note_^{1}. Letter to, on gunnery experiments, 452

Neath, improvement of river, 438 _note_^{1}

Newport viaduct, 185, 199

Neyland, pier at, 443

Ocean steam navigation, Mr. Brunel’s connection with, 231, 313

Opening bridges, 195

Oxford, Mr. Brunel created a Doctor in Civil Law at, 516

Oxford and Rugby extension of the Great Western Railway, 90, 116

Oxford branch of the Great Western Railway, 86

Oxford, Worcester, and Wolverhampton Railway, 90, 116

Paddington station, 84

Paris Exhibition of 1855, letter on decorations conferred at, 489

Parkes, Dr., medical superintendent of Renkioi Hospital, 468. Report of, on hospital buildings, 468

Patent laws, Mr. Brunel’s opinions on the, 212 _note_,^{1} 450, 451, 454, 485, 489, 497

Patterson, W., 234, 247, 263

Paxton, Sir Joseph, his design for the Great Exhibition building, 447

Permanent way on the Great Western Railway, 108, 535

Plymouth Great Western Docks, 433

Polygonal rifle, 449

Portishead, proposed pier at, 426

Prince Consort, H.R.H. the, opens the Royal Albert Bridge, 226. Present at floating of the ‘Great Britain,’ 259

Private life of Mr. Brunel, 499. Early reminiscences, 500. Removal to Duke Street, and marriage, 505. His taste in art, 506. First journey to Italy, 508. Half-sovereign accident, 511. Purchase of property in Devonshire, 514. Life at Watcombe, 515. Failing health, 516. Journeys to Switzerland and Egypt, 516. Letter from Philæ, 517. His last illness, 520

Quaker’s Yard, viaduct at, 89

Railways, sketch of, in England prior to 1833, 61. Extent of Mr. Brunel’s, 79. Great Western, 80. Branches to Oxford, 86. Windsor, 86. Wycombe, 86. Uxbridge, 86. Henley, 86. Brentford, 86. Bristol and Exeter Railway, 86. South Devon, 87. South Devon and Tavistock, 87. Cornwall, 87. Branch lines now incorporated with Great Western Railway: Berks and Hants, 88. Wilts and Somerset, 88. Cheltenham and Great Western Union, 88. Gloucester and Dean Forest, 88. The South Wales, 88. The Taff Vale, 89. The Vale of Neath, 89. The Llynvi Valley, 89. The South Wales Mineral, 89. Bristol and South Wales Union, 90. Bristol and Gloucester, 90. The Oxford and Rugby, 90. Birmingham and Oxford Junction, 90. Oxford, Worcester, and Wolverhampton, 90. Ireland, 90. Italy, 91. India (Eastern Bengal), 91

Railway Structures, letter on the Royal Commission on the Application of Iron to, 192, 486

‘Rattler’ steam-ship, trials with the, 287

Rendel, J. M., 211, 433

Renkioi, hospital buildings at, 461. Description of the buildings, 463. Dr. Parkes’s report on the formation and general management of the hospital, 468

Rennie, G. and J., 148

Richards, Westley, letters to, on polygonal rifle, 450

Riveting, experiments on, 194, 228

Ropes and chains, experiments on, 228

Rotherhithe shaft of the Thames Tunnel, construction of the, 9

Royal Albert Bridge at Saltash, 211. Plans for crossing the river Tamar at Saltash, 211. Trial cylinder for centre pier, 213. Report on making bridge for a single line, 214. Mode of construction of centre pier, 214. Description of superstructure, 218. Floating of first truss, 221. Lifting of first truss, 224. Floating and lifting of second truss, 225. Opening by H.R.H. the Prince Consort, 226

Royal Society, 516 _note_^{1}

Russell, J. Scott, builds the ‘Victoria’ and ‘Adelaide,’ 290. Assists Mr. Brunel in maturing designs of the ‘Great Eastern,’ 291, 292, 297. Letter to, on the form and dimensions of the ship, 294. Tender accepted for hull and paddle-engines, 301

St. Mary’s viaduct, 181

St. Pinnock viaduct, 186

Saltash bridge. _See_ Royal Albert Bridge

Samuda, J., 131, 134, 148, 160

Saunders, C. A., 92, 117, 119

Screw propeller, the, adopted for the ‘Great Britain,’ 254. Communications on, with the Board of Admiralty, 283. Trials with the ‘Polyphemus,’ 284. With the ‘Rattler,’ 287. Report recommending adoption of, 539

Shield, Thames Tunnel, the, 11, 12

‘Sirius’ steam-ship, 241

Skew bridges, 177

Smith, F. P., the screw propeller, 253, 287. Consulted by Mr. Brunel on the ‘Great Eastern,’ 297, 298

Smith, Sir F., member of the Gauge Commission, 117

Smyth, C. Piazzi, Astronomer Royal for Scotland, correspondence with Mr. Brunel on astronomical instruments for the ‘Great Eastern,’ 322

Sonning Cutting brickwork bridge, 175. Timber bridge, 179

South Devon and Tavistock Railway, 87. Viaducts, 188

South Devon Railway, 87. Course of the line, 132. Atmospheric System adopted on the, 138. Viaducts, 182

South Wales Mineral Railway, 89

South Wales Railway, 88. Viaducts, 183, 194

Standard drawings, 172 _note_^{2}

Stationary and locomotive power, comparison of, 142, 166

Statue of Mr. Brunel, 520 _note_^{1}

Stephenson, George, 61, 62, 70, 74, 99

Stephenson, Robert, 62, 106, 107, 134 Atmospheric System, 136, 137 _note_^{1}, 138, 144. Conway and Britannia bridges, 221, 223. Launch of the ‘Great Eastern,’ 375, 376, 377, 378, 384 _note_^{1}, 485, 516, 517, 521

Stonehouse viaduct, 181

Taff Vale Railway, 89, 104 _note_^{1}

Tamar, plans for crossing the river, 5 _note_^{2}, 46, 211

Telford, T., appointed referee to decide upon the plans for the Clifton Suspension Bridge, 51. Rejects Mr. Brunel’s plan, 51. Designs one himself, 52. His plan described, 52

Thames Tunnel, project of, first occupies Sir Isambard Brunel’s attention, 5. Plans suggested for the construction of a tunnel, 6. Borings, 7. Remarks on borings, 8 _note_^{1}. Commencement of the work, 9. Construction of the Rotherhithe shaft, 9. Description of the shield, 12. Journals of Sir I. Brunel of the progress of the work, 10, 11, 16. Mr. Brunel appointed resident engineer of, 25 _note_^{1}. First irruption of the river, 29. Second irruption, 35. Works suspended, 37. Resumed, 38. The Wapping shaft, 38. Completed and opened, 39. Its subsequent history, 39 _note_^{1}

Thompson, Dr. Seth. Letter on the half-sovereign accident, 511

Timber bridges and viaducts, 179

Timber, experiments on strength of, 182, 227

Torquay branch of the South Devon Railway, 87

Trussed bridges, 199

Uxbridge branch of the Great Western Railway, 86

Vale of Neath Railway, 89.

Viaducts, 171

Vick, Alderman William, his bequest for a bridge at Clifton, 47

‘Victoria’ steam-ship, built under Mr. Brunel’s direction, 290

Vignoles, C., 74

Walker, J., 107

Walkham viaduct, 189

Wapping shaft of the Thames Tunnel, construction of the, 38

Watcombe, Mr. Brunel’s life at, 514

Watt, James & Co., 148. Tender accepted for screw engines of the ‘Great Eastern,’ 301

West Cornwall Railway, 87. Viaducts, 189

Westminster Abbey, memorial window in, 520 _note_^{1}

Wilts and Somerset Railway, 88

Windsor branch of the Great Western Railway, 86

Windsor bridge, 200. Description of superstructure, 200. Mode of forming piers, 201

Wire gun, 453

Witness, Mr. Brunel’s reputation as a, 69, 93, 505

Wood, Nicholas, 101. Report on broad gauge and permanent way, 107

Wrought-iron bridges, 192

Wrought-iron girder, experiments on, 193

Wyatt, Sir M. D., 84

Wycombe extension of the Great Western Railway, 86

LONDON: PRINTED BY

SPOTTISWOODE AND CO., NEW-STREET SQUARE

AND PARLIAMENT STREET

* * * * *

Typographical errors corrected by the etext transcriber:

known method of makng=> known method of making {pg 45}

consits merely of=> consists merely of {pg 109}

every calcluation=> every calculation {pg 527}

* * * * *

FOOTNOTES:

[1] To avoid confusion, Sir Isambard Brunel has been called throughout by that designation, the one by which he is generally known: he was knighted on March 24, 1841.

His Life has been written by Mr. Richard Beamish, F.R.S. (London, 1862.)

[2] Lady Brunel survived her husband five years. Of their children, three lived to maturity, one son, Isambard Kingdom, and two daughters, Sophia, wife of the late Sir Benjamin Hawes, K.C.B., Under Secretary of State for War, and Emma, wife of the Rev. George Harrison, Rector of Sutcombe.

[3] He was sent to Paris to recover his knowledge of French, which had got rather rusty at school, and also to study mathematics. He retained through life a great admiration of the method of teaching this subject which was adopted in France.

In addition to the time spent in the study of mathematics and languages, Mr. Brunel occupied himself on his holidays in examining the various engineering works going on in Paris, and he used to send his father drawings and descriptions of them.

[4] Sir Isambard was also consulted upon a proposed suspension bridge over the Tamar at Saltash, where Mr. Brunel subsequently built the Royal Albert Bridge.

[5] This history has been written by Mr. Beamish in his _Life of Sir Isambard Brunel_, pp. 202-304, and also, up to the year 1828, in the very valuable work by Mr. Henry Law, C.E., entitled ‘A Memoir of the several Operations, and the Construction, of the Thames Tunnel,’ and published by the late Mr. Weale in his _Quarterly Papers on Engineering_.

[6] For an account of these earlier attempts see Law, pp. 3-7.

[7] This expectation does not seem to have been realised, as there was never any considerable traffic through the Thames Tunnel. Perhaps, however, it would have been otherwise had the large descents for carriages and horses been constructed.

[8] The results obtained by these borings were no doubt fallacious, but not to the extent which has sometimes been imagined. At a meeting of the Institution of Civil Engineers, in November 1849, Dean Buckland called attention to ‘the evils arising from the ignorance of the engineers who reported to Sir Isambard Brunel, previous to the commencement of the Thames Tunnel, that the whole of the bottom of the river at that spot was London clay.’ Whereupon Mr. Brunel rose and said, that he ‘agreed that knowledge of every kind was most desirable, and that it would be well if engineers were generally much better informed on many subjects which would be useful, and more particularly on matters connected with geology; at the same time he could not admit that they were deficient in that knowledge of the surface of the earth which was necessary for the purpose of guiding them in their work. It might be true that many members of the profession were, like himself, not perfectly well acquainted with the minute geological characteristics of the soils they had to deal with, but he thought the education and the practical experience of the profession generally rendered them well acquainted with those features and characteristics which were necessary for their guidance in the design or execution of work. He must also say a few words in defence of those persons (now nearly all dead) who made the borings in the Thames, and were stated to have made so fallacious a report previous to the commencement of the Tunnel. Now, although that statement had by constant repetition become a sort of historical fact, it was really only one of those popular fallacies which obtained too ready credence in the world. The position of the Tunnel was not determined by any report, or by the result of any borings, but with a view to establishing a communication between particular localities for encouraging the traffic which was anticipated from the facility of access to the docks, and for other local reasons, such as the general direction of the roads and streets on both shores. After the position was settled, and not until then, borings were made to ascertain what soils might be expected in that part of the river. It must be remembered that these borings were made full twenty-five years ago, when boring in the bed of a river through a depth of water of nearly thirty feet was not an ordinary occurrence. The tool then generally employed was the worm, and tubes were not even used in such cases. The borings showed the existence in that spot of something which, in the ordinary acceptation of the term, might have been inadvertently called London clay, but he had no recollection of its geological designation having ever been thought of. It was reported and shown to be a very fair clay for working in.... The errors which were made in giving the results of the borings did not, in fact, arise from ignorance, but from mechanical defects in the tools, for it was subsequently discovered that the worm frequently carried a portion of the upper tenacious clay through the softer strata beneath, and brought it up again. The tenacious clay might have been called London clay, but no value was attached to that particular designation; they cared little in engineering for its denomination, provided it was of a good tenacious quality. This mistake in terms (supposing it to have occurred) could not have had any influence on after proceedings; for, before the Tunnel was far advanced, he conducted with great care a series of borings extending across the Thames, and, as he used improved tools and worked through tubes, the holes were kept so dry that a candle was frequently lowered down to the bottom in order to see the amount of infiltration. By this means he was enabled to construct a correct section of the bed of the Thames at that spot, showing every layer of shells and gravel as well as every variation of the surface of the silt, &c. He entered more at length into these details than might perhaps appear necessary, because he felt it was incumbent upon those who had the conduct of works to show that they did not proceed so ignorantly or so recklessly as had been assumed, in the design or execution of large undertakings.’

[9] The paragraphs in small type, without any reference, are from Sir Isambard’s journals. The sentences inserted at the side are his marginal summary. Occasionally a few words are added (in square brackets) by way of explanation.

[10] The shaft subsequently made on the Wapping shore was sunk to its full depth without any under-pinning.

[11] Professor Rankine, in his work on _Civil Engineering_, p. 599, describes the Thames Tunnel works under the significant heading ‘Tunnelling in Mud.’

[12] _Proceedings Inst. C. E._ i. 34. The circumstances which led Sir Isambard to conceive the idea of a shield, and the earlier designs he made for it, are described, with illustrations, by Mr. Law, pp. 7-10.

[13] Mr. Law’s memoir contains a detailed description of every part of the shield, illustrated by careful drawings.

[14] Mr. Beamish had joined the works on August 7.

[15] On November 20 Mr. Brunel mentions in his diary that he had ‘passed seven days out of the last ten in the Tunnel. For nine days on an average 20⅓ hours per day in the Tunnel and 3⅔ to sleep.’

[16] On the previous day Mr. Brunel had been formally appointed resident engineer.

[17] Mr. Gravatt had been appointed an assistant engineer six months before.

[18] Sir Isambard’s journal of this eventful night consists--as he was not himself present--of Mr. Beamish’s journal, with a few words in warm commendation of that gentleman’s ‘judgment, coolness, and courage,’ followed by observations upon the stability of the shield. He then gives a statement made by Mr. Gravatt, and taken down in shorthand. No extracts are given in the text from Mr. Beamish’s narrative, as he has already inserted it in a condensed form in his _Life of Sir Isambard Brunel_, pp. 244-248.

[19] Mr. Michael Lane, at this time foreman bricklayer, became one of Mr. Brunel’s most valued assistants, and was employed by him on the Monkwearmouth Docks and the Great Western Railway. After filling various posts in the service of that company, he was in 1860 appointed their principal engineer, an office which he held till his death, in February, 1868.

[20] On this occasion an amusing incident occurred. Mr. Brunel was exceedingly unwilling to permit his visitors to make this expedition into the arch; but on the assurance that they could all swim perfectly well, he consented to take them, with the understanding that, if he jumped overboard, they were immediately to follow his example, and swim after him to the shaft. While they were in the arch Mr. Brunel (as Sir Isambard mentions) fell overboard. As soon as he recovered himself, and turned to swim back to the boat, he remembered that he had unwittingly given to his companions the signal to jump out into the water. He was much amused, on looking up, to see that they were not swimming after him, but were still sitting in the boat clinging to the gunwale, with faces expressive of blank despair.

[21] Mr. Brunel’s comment in his diary is as follows:--‘Without ascribing any particular merit to myself, I cannot help observing, for my future guidance, that being alone, and giving few but clear orders, and those always to the men who were to execute them, I succeeded in an operation not altogether mean, and which a very trifling want of precaution or order might have caused to be a total failure.’

[22] On January 15, 1828, the Directors of the Thames Tunnel Company passed the following resolution, which they ordered to be advertised in the _Times_, _New Times_, _Herald_, _Ledger_, and _Courier_:--‘That this court, having heard with great admiration of the intrepid courage and presence of mind displayed by Mr. Isambard Brunel, the company’s resident engineer, when the Thames broke into the Tunnel on the morning of the 12th instant, are desirous to give their public testimony to his calm and energetic endeavours, and to that generous principle which induced him to put his own life in more imminent hazard to save the lives of the men under his immediate care.’

[23] The Thames Tunnel was not successful as a commercial undertaking; but it has always been considered, especially by foreigners, one of the most interesting sights in London, and has been visited by several millions of persons. In 1865 it was purchased by the East London Railway Company, and trains now (March, 1870) run through it. The possibility of using the Tunnel as a railway had been considered in Mr. Brunel’s lifetime, and the idea was approved of by him.

[24] This description is based on the translation given by Mr. Drewry (_Suspension Bridges_, London, 1832, p. 75), from the _Mémoire sur les Ponts Suspendus_, by M. Navier (Paris, 1823, p. 49). M. Navier saw the bridges when they were erected at Sheffield in May 1823.

[25] The dimensions of these designs were as follows:--

(_a._) Length of floor 890 feet. Distance between points of suspension 980 " Length of chain 1,300 " With a capacity to bear excessive load of 650 tons.

(_b._) Length of floor 916 feet. Distance between points of suspension 1,160 " Length of chain 1,468 " With capacity to bear excessive load of 650 tons.

[26] On plate I. is given (fig. 1) a facsimile on a smaller scale of the drawing sent in by Mr. Brunel for the last-mentioned (_b_) of these two designs.

[27] See below, p. 60.

[28] See above, p. 42.

[29] The dimensions proposed in this design were as follows:--

Distance between points of suspension 600 feet. Versed sine 60 " Width of roadway 32 "

[30] A few days before this ceremony, an iron bar, 1½ inch diameter, and about 1,000 feet in length, was hung across the valley from Clifton Rocks to Leigh Down, to facilitate the works. It was traversed by a basket pulled by ropes. The first few journeys of this machine were somewhat perilous. It was intended that Mr. and Mrs. Brunel should be the first passengers; but, when all was ready, one of Mr. Brunel’s assistants started on a clandestine trial trip, and owing to a bend in the bar, the basket stuck half way, and the mast of a passing steamer caught in the rope. The rope was however cut, and he was drawn back. When the apparatus had been put to rights, on another occasion, when Mr. Brunel was in the basket, it got jammed, and he had to climb up the connecting link and get upon the bar, before he could release the basket.

[31]

Span 702 feet 3 inches. Versed sine 70 " Roadway above high-water 248 "

[32] Plate I. fig. 2 (p. 49), shows an elevation of the bridge according to the designs on which it was commenced.

[33] See Mr. Brunel’s remarks:--_Proceedings Inst. C. E._ for 1841, pp. 78, 79.

[34] Rollers on an arched surface had been used previously in several bridges.

[35] The chains were used in the construction of the Saltash bridge.

[36] Speech of the Chairman, the late Captain Mark Huish, at the first general meeting, August 2, 1861.

[37] Some re-arrangement of Mr. Brunel’s design was rendered necessary in order to adapt the Hungerford bridge chains to the Clifton bridge, and there are three chains instead of two, as in Mr. Brunel’s design. The platform is stiffened by wrought-iron girders instead of by timber trussing, and the whole bridge is stiffened transversely by the wrought-iron girders at the sides, which are connected throughout by diagonal bracing. The clear width of the bridge is 30 feet, 5 feet less than originally intended. It should be added, that no attempt has been made to complete the towers according to Mr. Brunel’s architectural designs.

[38] A graphic account of this famous parliamentary contest will be found in the third volume of Mr. Smiles’ _Lives of the Engineers_,