Part 20

ENERGY, PHYSICAL, is the capacity which a body or system of bodies has for doing work. Work is done when a force is overcome, and it is measured by the product of the force and the distance through which it is overcome. A quantity of energy is therefore expressed in terms of the same units as work, e.g. the foot-pound and the erg. Energy exists in two forms. Potential energy is that which a body possesses in virtue of its position. For instance, by winding up a clock weight it is given a certain amount of potential energy, which it slowly expends in driving the clock; a bent spring and a mass of compressed air also possess energy in the potential form. This kind may also be noted in the voltaic cell and the charged condenser, and in a chemical form in coal and gunpowder. Kinetic energy is possessed by bodies in virtue of their motion. Thus a moving bullet and a falling hammer contain kinetic energy; bodies which are in a state of vibration are also sources of this form of energy, which is diffused from the body through the surrounding medium in the form of waves, whether of sound, heat, light, or the ether waves of radio-telegraphy. Energy may thus exist in any of the following forms: mechanical (potential, kinetic), sound, heat, light, magnetic, electrostatic, electromagnetic, chemical.

Energy may be transformed from one kind into another. When a pendulum is vibrating, there is a continual transformation of potential into kinetic energy, and vice versa. By rubbing the hands together we convert mechanical energy into heat. In an electric tramway system we may note a whole series of transformations. The chemical energy of the fuel is turned into heat in the furnace and boiler; this, again, into kinetic energy of the turbine and dynamo; the latter gives out electric current, the energy of which, after suffering slight losses as heat in the overhead wire, and as light and sound in the spark at the trolley, passes into the motor, to reappear as kinetic energy of the car.

The transformation of energy takes place according to a definite law. The principle of the conservation of energy states that the total amount of energy in a self-contained finite system is constant. This implies that energy cannot be destroyed, and that when a certain amount of energy disappears, an equal amount appears in another form. This principle is apparently contradicted in many cases of transformation, since it is impossible to transform energy by natural process, or by the use of mechanism, without doing work in overcoming frictional or resisting forces. In all such cases the energy spent is converted into heat, which is less available as useful energy. The experiments of Rumford, Davy, and Joule were instrumental in establishing the equivalence of mechanical energy and heat. Rumford showed that water could be boiled by means of the heat produced by rotating a blunt boring-tool within a cannon, and pointed out that the heat liberated was, in another form, the energy spent in driving the blunt drill. Davy caused two pieces of ice to be rubbed together within a vacuum at a temperature below zero, and melted the ice, thus showing that, since ice has to absorb heat in order to melt, the supply of heat could not have come from the ice itself, but must have resulted from the work done in rubbing. It has to be remembered that, in the time of Rumford and Davy, the belief was prevalent that heat or caloric was a material substance, and not a form of motion.

A further and most important step was made by Dr. J. P. Joule, of Manchester, who measured the amount of mechanical work which is spent in producing one unit of heat. This is known as the mechanical equivalent of heat, or Joule's equivalent. Two hanging weights were geared to a set of paddles which could rotate within a cylindrical copper vessel filled with water, and supplied with fixed vanes. The weights were released, and in descending a measured distance caused the paddles to churn the water in the vessel, and thus the water was slightly warmed. This operation was repeated several times, and the rise of temperature of the water was measured by means of a delicate thermometer. When corrections for friction, cooling, and other losses had been applied, Joule calculated that 772 foot-pounds of work were expended in raising 1 lb. of water 1deg F. The experiment has been repeated in various forms, and the value now accepted for Joule's equivalent is 777.

Although energy cannot be destroyed, nor, it may be added, created, it may be rendered less available for use. The various forms of energy may be classified according to their availability, and in this respect mechanical energy is one of the most available, and low-temperature heat is one of the least available. The latter is therefore classed as a lower form of energy, and when energy is converted from a more available to a less available form, it is said to be dissipated or degraded. Now, during any transformation of energy, a part of the energy is spent in overcoming friction forces, and is thus degraded.

The problem of economizing our stores of energy is one which is now attracting more attention than it did formerly. With the greater scarcity of coal, and the future prospect of its complete absence, other natural sources of energy are being investigated. Oil has been discovered in this country, but not in large quantities. Waterfalls have long been employed for driving mills wherever this type of power could be obtained cheaply and conveniently; the resources of the Highlands in this respect have not been utilized to any great extent. At Kinlochleven, where the valley has been dammed across to obtain sufficient water-power, an aluminium industry has sprung up. There is a scheme on foot at the present time to make use of the tidal energy of the Severn. Here and there windmills may be seen which drive water-pumps employed for draining purposes. On the Severn, near Ironbridge, a ferry is in use which employs the force of the river current to propel the ferryboat across the river. In warmer countries batteries of mirrors have been employed to concentrate the sun's heat for use in the absence of fuel. In large towns the presence of unconsumed carbon (soot) in the atmosphere raises the question not only of fuel economy but also of public health.--BIBLIOGRAPHY: Kelvin and Tait, _Natural Philosophy_; Balfour Stewart, _Conservation of Energy_; Deschanel, _Heat, Light, &c._; E. Buckingham, _Thermodynamics_.

ENFANTIN ([.a][n.]-f[.a][n.]-ta[n.]), Barth['e]lemy Prosper, one of the chief founders of St. Simonism; born at Paris 1796, died in 1864. In 1825 he became acquainted with St. Simon, who in dying confided to him the task of continuing the work. This he did with success until after the Revolution of 1830, when, as the representative of the social and religious theories of the school, he quarrelled with Bazard, the representative of its political ideas. Enfantin organized model communities, which quickly fell to pieces; the new organ of the sect, _Le Globe_, was a failure; their convent at M['e]nilmontant, of which Enfantin was 'supreme father', was broken up by the Government (1832). He himself was imprisoned as an offender against public morality (being an advocate of free love), and on his release attempted to found a model colony in Egypt, which was broken up in the second year. He then retired to Tain (Dr[^o]me), where he lived for some time as a farmer. In 1841 he was sent as member of a commission to explore the industrial resources of Algiers, and on his return published a work on the _Colonization of Algiers_ (1848). On the Revolution of 1848 he started a new journal, _Le Cr['e]dit Public_, but after two years withdrew from public notice. He afterwards held a post on the Lyons and Mediterranean Railway until his death. Among his works are: _Doctrine de St. Simon_, _La Religion St. Simonienne_.

EN'FIELD, a town, England, county Middlesex, 9 miles N. by E. London. It is the seat of the Government manufactory of rifles and small-arms. It gives its name to the British rifle (Lee-Enfield), which helped to win the European War. Pop. 56,338.

ENFILADE FIRE, fire directed down the length of a trench or a line of troops from a point at right angles to their front. Its moral effect is very great, as it usually comes from an unexpected direction, and the target presented to it is generally more vulnerable. Trenches give much less protection against oblique or enfilade fire than they do against frontal fire, although the main purpose of 'bays' is to lessen the effect of enfilading.

EN'GADINE, a beautiful valley in Switzerland, in the Grisons, on the banks of the Inn, bordering on the Tyrol, about 50 miles long, but in some parts very narrow, divided into Upper and Lower. The pop. of the whole valley amounts to about 12,000. The language generally spoken is the Ladin, a branch of the Romanic tongue. The cold, dry climate and mineral springs have made the valley a favourite resort for invalids.

ENGAGED COLUMN, in architecture, a column attached to a wall so that part of it (usually less than half) is concealed.

ENGELS, FRIEDRICH, German Socialist, born at Barmen in 1820, died 1895. He was the son of a rich cotton-spinner, and although destined for a commercial career, he began to collaborate on the _Deutsch-Franzosische Jahrb[:u]cher_ issued in Paris by Karl Marx and Arnold Ruge. He helped Marx to organize the Communist League in 1846, and took part in the Revolution of 1848 at Baden. From 1850 to 1869 he lived at Manchester as manufacturer. An intimate friend of Marx, he helped the latter to spread social democratic ideas, and was part author, of the _Communist Manifesto_. After the death of Marx he edited the second and third volumes of _Das Kapital_. Engel's own works include: _The Condition of the Working Classes in England in 1844_; _The Origin of the Family_; _Private Property and the State_; and _Socialism, Utopian and Scientific_.--Cf. Karl Kautsky, _Friedrich Engels: his Life, his Work, and his Writings_.

ENGHIEN ([.a][n.]-gi-[.a][n.]), or _Enguien_, a town in Hainault, Belgium, between Brussels and Tournai. It has a superb castle, and gave the title of duke to a prince of the house of Bourbon Cond['e] in memory of the victory gained here by the great Cond['e]. Pop. 4540.

ENGHIEN ([.a][n.]-gi-[.a][n.]), Louis Antoine Henri de Bourbon, Duke of, born at Chantilly in 1772; son of Louis Henry Joseph Cond['e], Duke of Bourbon. On the outbreak of the Revolution he quitted France, travelled through various parts of Europe, and went in 1792 to Flanders to join his grandfather, the Prince of Cond['e], in the campaign against France. From 1796 to 1799 he commanded with distinguished merit the vanguard of Cond['e]'s army, which was disbanded at the Peace of Lun['e]ville (1801). He then took up residence as a private citizen at Ettenheim in Baden, where he married the Princess Charlotte de Rohan Rochefort. He was generally looked upon as the leader of the _['e]migr['e]s_ (q.v.), and was suspected by the Bonapartists of complicity in the attempt of Cadoudal to assassinate the first consul. An armed force was sent to seize him in Baden in violation of all territorial rights, and he was brought to Vincennes on the 20th March, 1804. A trial, which was a mere form, was held the same night; and on the following morning he was shot in the ditch outside the walls. It was this event which drew from Fouch['e] the comment, since become proverbial: "C'est plus qu'un crime, c'est une faute" ("It is worse than a crime, it is a blunder").

EN'GINE. See _Internal Combustion Engines_; _Steam-engines_.

ENGINEERING, the profession concerned in applying the forces of nature to the service of man. It is divided into two groups, civil engineering and military engineering. This grouping of the profession of engineering is adopted in the Charter of the Institution of Civil Engineers. Army engineers are organized as Royal Engineers. Candidates intending to become Royal Engineer officers have to pass the Army Entrance Examination to gain admission to Woolwich. At Woolwich they receive a course of technical instruction, and then proceed to military engineering duties in the Royal Engineers. Naval engineers enter the service as naval cadets. The education of all naval cadets is the same, no matter in what branch of the service they may ultimately specialize, up to the rank of sub-lieutenant, when specialization begins. The engineering lieutenants undergo a special course of engineering training at the Royal Naval College, Greenwich, and then go to sea. Naval engineers are called upon to undergo a severe medical examination, as the conditions of service call for robust men.

In the ordinary way the term _civil engineering_ is not used in the technical sense explained above, but is the name given to one of the sections into which the whole group is divided. The 'civil' engineer undertakes the design and erection of constructional works, such as harbours, docks, railways, buildings, bridges, &c. A person entering the profession of civil engineering usually receives a technical education at a technical school, or at a university, and then enters the office of a practising civil engineer. He will spend a part of his time at the drawing-board, learning the details of design, and a part of his time actually in the field or on works, assisting in the supervision of the work. The other departments of the group of 'civil engineers'--as distinct from military engineers--are mechanical engineers, electrical engineers, motor engineers, telegraph engineers, radio engineers, mining engineers, aeronautical engineers, &c. With the exception of mining, the courses of training in these sections are very much the same, and consist of a technical course in a college or a university, followed by a practical training as a pupil in a works. The prior technical education is now being insisted upon by most of the large engineering firms, and, in many of the best works, special courses of instruction are given to apprentices as part of their training by the most experienced engineers of the company. In mining, the orthodox training consists of a technical course in one of the mining schools, followed by practical work in a mine. In this country every mining engineer who intends to take a position of responsibility must qualify by passing a Board of Trade examination. Sea-going marine engineering officers have, in addition to undergoing the usual training, to pass the sea-going engineers' examination of the Board of Trade. It will be seen from the above remarks that the courses of training for engineers depend entirely upon the particular branch of engineering which is to be entered. As this point is often not finally settled till fairly late in a young man's career, it is possibly unwise for him to take his initial training in too narrow a groove. A sound, general technical education, combined with three or four years' experience in a general engineering works, will fit him for specializing in very many sections of engineering, whereas if he intends to enter the mining or the civil engineering professions, a sound technical course, followed by a few years' experience in civil or mining engineering work abroad will usually fit him for a specialized post later on.

ENGINEERS, ROYAL. Military engineers in one form or another, and under various names, have existed in England since the eleventh century. In those early days men of some education--often monks--were appointed as Ingeniatores Regis to undertake the manufacture of the king's engines of war, and to build his castles. In later years they became known as Attilators, and when, with the gradual introduction of gunpowder for military purposes, a combined train was formed, are considered to have given their name to what we now call artillery. In the early seventeenth century this train, composed of engineers and artillery, was merely a temporary corps raised for a particular war and disbanded on its conclusion; but in 1698, when the expediency of maintaining a standing army had been to some extent recognized, the first permanent train was raised. In 1716 a separate body of engineers was formed, but without military rank, and it was not till 1782 that military titles were conferred on the officers of engineers. In 1787 the Corps of Engineers became by Royal Warrant the Corps of Royal Engineers, with the mottoes _Ubique_ and _Quo fas et gloria ducunt_, which are also borne by the Royal Regiment of Artillery. For a considerable period the rank and file of the corps were known as the 'Royal Sappers and Pioneers', and the term 'Sapper' is still used to denote a private of the corps. Among the present-day peace-time duties of the Royal Engineers are the construction and maintenance of barracks and military works generally, while for war purposes the corps is organized into mobile units known as field squadrons and companies for general field-work, and into more highly specialized units for mining, heavy bridging, and railway work. The corps is recruited almost entirely from among artisans and tradesmen, and a field company of a total strength of 184 all ranks has representatives of no fewer than nineteen trades in it.

ENGLAND, including _Wales_, the southern and larger portion of the Island of Great Britain, is situated between 50deg and 55deg 46' N. lat., and 1deg 46' E. and 5deg 42' W. long. On the north it is bounded by Scotland; on all other sides it is washed by the sea: on the east by the North Sea; on the south by the English Channel; and on the west by St. George's Channel and the Irish Sea. Its figure is, roughly speaking, triangular, but with many windings and indentations, the coast-line measuring not less than 2765 miles. The length of the country, measured on a meridian from Berwick nearly to St. Alban's Head, is 365 miles. Its breadth, measured on a parallel of latitude, attains its maximum between St. David's Head, in South Wales, and the Naze, in Essex, where it amounts to 280 miles. The area is 37,340,388 acres or 58,310 sq. miles, of which 32,559,868 acres or 50,874 sq. miles are in England, and 4,780,470 acres or 7466 sq. miles in Wales. This is exclusive of the Channel Islands and the Isle of Man, which together would add 193,647 acres or 302 sq. miles more to the area. The subdivision of England into shires or counties does not appear to have assumed a definite form till the time of Alfred. The existing division was first completed under Henry VIII. There are now 'administrative counties' and 'registration counties', differing in area from the old counties; London being now a county. The figures in the table (p. 241) refer to the old counties.

The capital of England and of the British Empire is London. The cities next in size (in order of population) are: Liverpool, Manchester and Salford, Birmingham, Leeds, Sheffield, Bristol, Bradford, Nottingham, and Hull.

_Physical Features._--The chief indentations are: on the east, the Humber, the Wash, and the Thames estuary: on the west, the Solway Firth, Morecambe Bay, Cardigan Bay, and the Bristol Channel; those on the south are less prominent, though including some useful harbours. The greater part of the coast consists of cliffs, in some places clayey, in others rocky, and sometimes jutting out, as at Whitby and Flamborough Head on the east, Beachy Head, the Isle of Portland, the Lizard and Land's End on the south and south-west, St. David's Head and St. Bees Head on the west, into bold, lofty, and precipitous headlands. The most extensive stretches of flat coast are on the east, in the county of Lincoln, and from the southern part of Suffolk to the South Foreland in Kent, and in Sussex and Hants on the south coast. The chief islands are: Holy Island, the Farne Islands, Sheppey, and Thanet on the east coast; the Isle of Wight on the south; the Scilly Isles at the south-west extremity; and Lundy Island, Anglesey, Holy Island, and Walney on the west.

The loftiest heights of England and Wales are situated at no great distance from its western shores, and consist not so much of a continuous chain as of a succession of mountains and hills stretching, with some interruptions, from north to south, and throwing out numerous branches on both sides, but particularly to the west, where all the culminating summits are found. The northern portion of this range has received the name of the Pennine chain. It is properly a continuation of the Cheviot Hills, and, commencing at the Scottish border, proceeds south for about 270 miles till, in the counties of Derby and Stafford, it assumes the form of an elevated moorland plateau. In Derbyshire The Peak rises to the height of 2080 feet. By far the most important of its offsets are those of the west, more especially if we include in them the lofty mountain masses in North-Western England sometimes classed separately as the Cumbrian range. Amidst these mountains lie the celebrated English lakes, of which the most important are Windermere, Derwent Water, Coniston Lake, and Ullswater. Here also is the highest summit of Northern England, Scawfell (3210 feet). The Pennine chain, with its appended Cumbrian range, is succeeded by one which surpasses both these in loftiness and extent, but has its great nucleus much farther to the west, where it covers the greater part of Wales, deriving from this its name, the Cambrian range. Its principal ridge stretches through Carnarvonshire from N.N.E to S.S.W., with Snowdon (3571 feet) as the culminating point of South Britain. Across the Bristol Channel from Wales is the Devonian range. It may be considered as commencing in the Mendip Hills of Somerset, and then pursuing a south-westerly direction through that county and the counties of Devon and Cornwall to the Land's End, the wild and desolate tract of Dartmoor forming one of its most remarkable features (highest summit, Yes Tor, 2050 feet). Other ranges are the Cotswold Hills proceeding in a north-easterly direction from near the Mendip Hills; the Chiltern Hills taking a similar direction farther to the east; and the North and South Downs running eastward, the latter reaching the south coast near Beachy Head, the former reaching the south-east coast at Folkestone.

Column Headings:

A - Area in Statute Acres, 1921 (Land and Inland Water). Counties, including County Boroughs, B - _Census Population._ Counties, including County Boroughs, 1911. C - _Census Population._ Counties, including County Boroughs, 1921.