Part 10

The furnace consists essentially of three parts; (1) the gas producer, which converts the solid coal into gaseous fuel; (2) the regenerators, usually four in number, which are filled with fire-brick piled in such a way as to break up into many parts a current of air or gas passing through them; (3) the furnace proper, where the combustion is actually accomplished. In using the furnace, the gaseous fuel and air are conducted through one pair of regenerators to the combustion chamber; the heated gases from this, on their way to the chimney, pass through the other pair of regenerators, heating them in their passage. In the course of, say, one hour, the currents are reversed, so that the comparatively cold gas and air pass over these heated regenerators before entering the furnace, and rob them of their heat. While this is going on, the first pair of regenerators is being heated again, and thus, by working them in alternate pairs, nearly all the heat, which would otherwise have escaped unused into the chimney, is utilised.

By this process of accumulation the highest possible temperature (only limited by the point at which its materials begin to melt), can be obtained in the furnace chamber, without an intensified draft, and with inferior fuel.

It has been found that this furnace is capable of making a ton of crucible steel with _one-sixth_ of the fuel required without it, and that while the temperature of the furnace chamber exceeded 4,000° Fahrenheit, the waste products of combustion escaped into the chimney at 240° Fahrenheit, or very little above the temperature at which water boils in the open air.

At the locomotive works of the London and North Western Railway at Crewe, where these furnaces have long been used, it was formerly the practice to lock a piece of pitch pine into the flue leading to the chimney, and if at the end of the week the wood was charred, it was evidence that more heat had been wasted than ought to have been, and the men in charge of the furnace were fined.

This all-important national question, the waste of fuel, which in modern phraseology may be truly called the waste of energy, was constantly before the mind of Sir William Siemens, who lost no opportunity, in his public utterances, of impressing his hearers, and that still wider circle which he reached through the medium of the press, with a sense of the weighty consequences which it involved. In an address at Liverpool in 1872, as President of the Institution of Mechanical Engineers, he estimated the total coal consumption of this country at one hundred and twenty million tons, which at 10s. per ton amounted to sixty millions sterling. He strongly asserted that one-half of this might be saved by the general adoption of improved appliances which were within the range of actual knowledge; and he went on to speak of outside speculations, which would lead to the expectation of accomplishing these ends with one-eighth or even one-tenth of the actual expenditure. In 1873 he delivered a famous lecture on Fuel to the operative classes at Bradford, on behalf of the British Association, in which he illustrated how fuel should be used by three examples, typical of the three great branches of consumption: _a_, the production of steam power; _b_, the domestic hearth; _c_, the metallurgical furnace. In connection with the last point he mentioned that the Sheffield pot steel-melting furnace only utilised _one-seventieth_ part of the theoretical heat developed in the combustion, and contrasted with it his own furnace for melting steel. In discussing the question of the duration of our coal supply, he indicated what should be our national aim in the following suggestive and inspiring passage:

“In working through the statistical returns of the progressive increase of population, of steam power employed, and of production of iron and steel, &c., I find that our necessities increase at a rate of not less than 8 per cent. per annum, whereas our coal consumption increases only at the rate of 4 per cent., showing that the balance of 4 per cent. is met by what may be called our ‘intellectual progress.’ Now, considering the enormous margin for improvement before us, I contend that we should not be satisfied with this rate of intellectual progress, involving as it does an annual deficit of four million tons to be met by increased coal production, but that we should bring our intellectual progress up to the rate of our industrial progress, by which means we should make the coal production nearly a constant quantity for several generations to come.”

One of the direct results of this lecture, which was read and warmly commended by some of the most eminent men of the time, was that Dr. Siemens was consulted by Mr. Mundella in reference to parliamentary action by the Board of Trade in regard to the coal question.

In 1874 he received the Albert Gold Medal from the Society of Arts “for his researches in connection with the laws of heat, and for services rendered by him in the economisation of fuel in its various applications to manufactures and the arts,” and in 1877 he devoted nearly the whole of his address to the Iron and Steel Institute, of which he was then President, to the same subject, in which, as regards the probable duration of our coal supply, he had been for some time engaged in a controversy with the late Professor Jevons, maintaining that “the ratio of increase of population and output of manufactured goods would be nearly balanced for many years to come by the further introduction of economical processes, and that our annual production would remain substantially the same within that period, which would probably be a period of comparatively cheap coal.”

One of the most important applications of the regenerative furnace has been to the manufacture of steel, and he soon perceived that it was necessary for himself to solve the various difficulties which others regarded as practically insuperable. “Having,” he says, “been so often disappointed by the indifference of manufacturers and the antagonism of their workmen, I determined in 1865 to erect experimental or ‘sample steel works’ of my own at Birmingham, for the purpose of maturing the details of these processes, before inviting manufacturers to adopt them.” The success of experiments in 1867-68, in making steel rails, brought about the formation of the Landore Siemens Steel Co., whose works were opened in 1874. When Dr. Siemens was knighted, the employés of this company embodied their congratulations in an address, and had prepared for him a very beautiful model of a steel furnace in ivory and silver; the presentation of these was prevented by his premature death, but the address stated that “the quantity of steel made here to the end of last year on your process was upwards of 400,000 tons!” In the ten years ending in 1882, the annual production of open-hearth steel in the United Kingdom increased from 77,500 tons to 436,000 tons. During an action in the Superior Courts of the United States, it was stated that the inventor had received a million dollars in royalties, the annual saving in that country by his process being 3¾ millions of dollars! These statements refer mainly, I believe, to the conversion of cast or wrought iron into steel, either by the “direct” process of acting on pig-iron with iron ore in an open hearth, or by the “scrap process” (Siemens-Martin) of melting wrought-iron and steel scrap in a bath of pig-metal. Both of these require the preliminary treatment of the blast furnace, and in speaking of them in 1873, Dr. Siemens said that “however satisfactory these results might appear, I have never considered them in the light of final achievements. On the contrary, I have always looked upon the direct conversion of iron and steel from the ore, without the intervention of blast furnaces and the refinery, as the great object to be attained.” How far he succeeded in this may be gathered from the fact that in a paper read on April 29, 1883, before the Iron and Steel Institute, on the “Manufacture of Iron and Steel by the Direct Process,” he showed how to produce 15 cwt. of wrought iron direct from the ore in three hours, with a consumption of 25 cwt. of coal per ton of metal, which is one-half the quantity previously required for the production of a ton of pig-iron only, in the blast furnace! The long and costly experiments which ended in the realisation of his views extended over twenty-five years; and it is worthy of note that he told the Parliamentary Committee on Patents that he would not have continued them if the English patent law had not insured such a period of protection as would repay him for his labor.

Great, however, as the economic results of the gas-producer have been, its inventor looked forward to still more remarkable applications of it. In 1882 he told the British Association, in his presidential address, that he thought “the time is not far distant when both rich and poor will largely resort to gas as the most convenient, the cleanest, and the cheapest of heating agents, and when raw coal will be seen only at the colliery or the gas-works. In all cases where the town to be supplied is within, say, thirty miles of the colliery, the gas-works may with advantage be planted at the mouth, or, still better, at the bottom of the pit, whereby all haulage of fuel would be avoided, and the gas, in its ascent from the bottom of the colliery, would acquire an onward pressure sufficient probably to impel it to its destination. The possibility of transporting combustible gas through pipes for such a distance has been proved at Pittsburg, where natural gas from the oil district is used in large quantities.” It may be well to point out here that as a step towards this, it was a favorite project of his—practically carried out in some places—to divide the gaseous products of the ordinary distillation of coal into two, the middle portions being illuminating gas of 18 to 20 candle power instead of 16, and the first and last portions, which under this system may be largely increased, being heating gas; such gas he expected to see sold at 1_s._ per 1,000 cubic feet. The obvious and only practicable objection to the plan is the necessity for doubling all the mains and service-pipes. That we shall eventually burn gaseous fuel on the domestic hearth, as we have lately learnt to do on the metallurgical, I have not the smallest doubt; it is a mere question of the time necessary for the education of the public mind upon the question; the apter the pupil, the more speedy will be the desired result. Let it be thoroughly understood by every one that the soot which hangs in a pall over London in a single day is _equivalent to at least fifty tons of coal_, and then there will be no difficulty in seeing that the true and the only remedy for our London fogs, with all their attendant ills, is—gaseous fuel. May we not hope that, though Sir William Siemens has gone from among us, the great movement for smoke abatement, in which he so earnestly labored during the last three years of his life, may have full effect?

If I have dwelt thus long upon this particular branch of my subject, it is because I know of no other which so well illustrates two points in Sir William Siemens’ character which I have alluded to at the outset: his unwavering devotion to general principles and their consequences, and his ardent desire to promote the practical welfare of mankind. There is, however, as the late Professor Rolleston remarked to him, no subject which more impresses the minds even of persons who are laymen as regards science, than the history of Telegraphy (and I may perhaps be permitted to add, of Electrical Engineering generally), now so inseparably connected with his name. The University of Göttingen, at which he studied, was the cradle, if not the birthplace, of the electric telegraph in 1833. Shortly after, Sir Charles Wheatstone in England, and Mr. Morse in the United States, were simultaneously working at the same problem, and each claimed the honor of having solved it.

The telegraph, however, was still in a very undeveloped state when the Brothers Siemens began to study it, and their series of inventions, especially for long-distance telegraphy, largely aided in bringing it to its present condition. One of their first was the Relay, an electro-magnet so delicate that it will move with the weakest current. By the use of five of Siemens’ polarised relays, a message can be sent by the Indo-European Telegraph from London to Teherán, a distance of 3,800 miles, without any retransmission by hand, and during the Shah of Persia’s visit in 1873, Dr. Siemens arranged for messages to be thus regularly despatched from a room in Buckingham Palace. In 1858, Messrs. Siemens Brothers established near London the well-known telegraph works, and the construction by them in 1868 and following years of the Indo-European Telegraph—the overland double line to India through Prussia, Southern Russia, and Persia—was the first great undertaking of the kind. Writing of it in August, 1882, during the first Egyptian campaign, Dr. Siemens said, “At the present time our communication with India, Australia, and the Cape depends, notwithstanding the nominal existence of the line through Turkey, on the Indo-European Telegraph.”

The Messrs. Siemens were also pioneers in submarine telegraphy, the first cable covered with gutta-percha having been laid across the Rhine by Dr. Werner Siemens in 1847. The invention of the machine for coating the conducting wire with the insulating material, gutta-percha, or india rubber, is entirely due to Dr. William Siemens, who also subsequently designed the steamship _Faraday_ for the special work of laying and repairing submarine cables. This unique vessel was launched on Feb. 16, 1874, and when she was completed, Dr. Siemens invited all his scientific friends to inspect her, and challenged them to suggest any improvements in her arrangements. She was first used in laying the Direct United States Cable, which is above 3,000 miles in length. In this connection I may perhaps be permitted to relate a very characteristic anecdote. When Dr. Siemens took a contract for a cable, the electrical tests of which were specified, it was his invariable habit to give out to the works a considerably higher test, which every section of the cable had to pass, or be rejected _in toto_. In the case of this cable, probably during manipulation on board ship, a minute piece of wire penetrated the insulating material, bringing down the electrical test to a point below the “works” test, but still decidedly above the contract test. The discovery was not made until so late that to cut out the faulty piece involved a delay of some days in the middle of the Atlantic, but Dr. Siemens insisted upon its being done; after this, stormy weather came on, and the cable had to be cut and buoyed, while the _Faraday_ had to winter on the American side, and resume operations next spring. The money loss involved amounted, I am told, to more than £30,000. Perhaps the most remarkable of the later feats was the fulfilment of a contract with the Compagnie Française du Telegraphe de Paris à New York, who ordered a cable 3,000 miles long from the Messrs. Siemens in March, 1879, and it was handed over to them in perfect working order in September of the same year! There are now nearly 90,000 miles of submarine cable at work, costing about £32,000,000, and a fleet of thirty-two ships are employed in laying, watching, and repairing these cables, of which there are now eleven across the Atlantic alone.

In connection with the subject of telegraphy, and as an instance of the versatility of Dr. Siemens’s inventive powers, I may point out that in 1876 he brought out the pneumatic postal telegraph tube, by which, as is pretty generally known, written messages are blown or sucked through tubes on various metropolitan routes, instead of being transmitted electrically. About the same time, also, he constructed his ingenious bathometer, for ascertaining the depth of the sea at any given point, without the tedious operation of sounding; and some years previously he worked out his electrical thermometer or pyrometer, enabling the observer to read the temperature (whenever he desired) at any distant and inaccessible point, such as the top of a mountain, the bottom of the sea, the air between the layers of a cable, or the interior of a furnace.

Probably the most prominent idea associated in the public mind with the name of Siemens is that of electric lighting, and perhaps electric tram and railroads. As I have more than once pointed out in this room, the dynamo-machine, by which mechanical energy is converted into that form of energy known as electricity (which may be used both for lighting and for the transmission of power), is derived from a principle discovered by Faraday in 1831. Sir William Siemens’ devotion to this, and the important practical consequences which he deduced from it, constitute another example of that mental characteristic to which I have already alluded. Faraday’s discovery, briefly described, was that when a bar magnet was suddenly inserted into a coil of wire, or when a wire was suddenly moved through a magnetic field, a momentary current of electricity was developed in the wire. Although this current is exceedingly small and brief, it is capable of unlimited multiplication by mechanical arrangements of a simple kind. One means for accomplishing this multiplication was the Siemens armature of 1857, which consisted, at first, of a piece of iron with wire wound round it longitudinally, not transversely, the whole to be rotated between the poles of a powerful magnet; in its present form it is one of the most powerful and perfect things of its kind, and the evolution of the Siemens armature, as we now have it, from the rudimentary type of a quarter of a century ago, has been characterised by Sir W. Thomson as one of the most beautiful products of inventive genius, and more like the growth of a flower than to almost anything else in the way of mechanism made by man.

Ten years afterwards came his classical paper “On the Conversion of Dynamical into Electrical Force, without the use of permanent Magnetism,” which was read before the Royal Society on February 14, 1867. Strangely enough, the discovery of the same principle was enunciated at the same meeting by Sir Charles Wheatstone, while there is yet a third claimant in the person of Mr. Cromwell Varley, who had previously applied for a patent in which the idea was embodied. It can never be quite certain, therefore, who was the first discoverer of the principle upon which modern dynamo-machines are constructed. I need not describe here the way in which this principle is carried out in all dynamo-machines. Suffice it to say that they differ from Faraday’s magneto-electric machines in having electro-magnets in the place of permanent steel magnets, and that these electro-magnets are, if I may be allowed the expression, self-excited by the play of mutual give and take between the armature and the magnet.

It was the invention of the dynamo-machine which made practicable the application of electricity to industrial purposes. Experiments have shown that it is capable of transforming into electrical work 90 per cent. of the mechanical energy employed as motive power. Its practical application is still in its infancy. In 1785 Watt completed his “improvements” in the steam-engine, and the century which has since elapsed has not sufficed to demonstrate the full extent of its utility. What may we not expect in the next hundred years from the extension of the dynamo-machine to practical purposes?

In the development of appliances for the production of the electric light Sir William Siemens took a leading part, and, as is well known, his firm has been _facile princeps_ at all the important electrical exhibitions. But while ever zealous to promote its progress, he never took a partisan view of its utility, candidly admitting that gas must continue to be the poor man’s friend. In 1882 he told the Society of Arts that “Electricity must win the day _as the light of luxury_, but gas will find an ever-increasing application for the more humble purposes of diffusing light.”

In the hands of Dr. Siemens the enormous energy displayed in the Electric Arc was applied to other purposes than mere lighting. In June, 1880, he greatly astonished the Society of Telegraph Engineers by exhibiting the power of an electrical furnace designed by him to melt considerable quantities of such exceedingly refractory metals as platinum, iridium, &c. He explained that he was led to undertake experiments with this end in view by the consideration that a good steam-engine converts 15 per cent. of the energy of coal into mechanical effect, while a good dynamo-machine is capable of converting 80 per cent. of the mechanical into electrical energy. If the latter could be expended without loss in an electric furnace, it would doubtless far exceed in economy any known air furnace.

Moreover Sir William Siemens may fairly be described as the creator of electro-horticulture. Some experiments which he made early in 1880 led him to the conclusion that the electric light could influence the production of coloring matter in leaves, and promote the ripening of fruit at all seasons of the year, and at all hours of the day and night. In the following winter he put these conclusions to the test of experience on a large scale at his country house, Sherwood, near Tunbridge Wells, and the results obtained were communicated to the British Association at York in 1881, in a paper, the value of which was recognised by its receiving the rare distinction of being printed in full in the annual report.

Some photographs, which he kindly allowed me to take, represent the difference between three kinds of corn grown under ordinary conditions, and the same corn, under the same conditions, with the added stimulus of the electric light from sunset to sunrise. He came to the conclusion that, although periodic darkness evidently favors growth in the sense of elongating the stalks of plants, the _continuous_ stimulus of light was favorable to a healthy development at a greatly accelerated pace, through all the stages of the annual life of the plant, from the early leaf to the ripened fruit.

I have left until the last any notice of a field of work which the Messrs. Siemens may be truly said to have made peculiarly their own, viz., the electrical transmission and distribution of power; for I firmly believe that in the future, although not perhaps in the near future, the practical consequences of this will be such as are little dreamed of now; and this opinion is, I know, held by men far more competent to judge than I am.