In other topics the same restrictions on the scope of the simple

statical theory of energy appear. From the ascertained behaviour in

certain respects of gaseous media we are able to construct their

characteristic equation, and correlate their remaining relations by

means of its consequences. Part of the experimental knowledge required

for this purpose is the values of the gas-constants, which prove to be

the same for all nearly perfect gases. The doctrine of energetics by

itself can give no clue as to why this should be so; it can only

construct a scheme for each simple or complex medium on the basis of its

own experimentally determined characteristic equation. The explanation

of uniformities in the intrinsic constitutions of various media belongs

to molecular theory, which is a distinct and in the main more complex

and more speculative department of knowledge. When we proceed further

and find, with van 't Hoff, that these same universal gas-constants

reappear in the relations of very dilute solutions, our demand for an

explanation such as can only be provided by molecular theory (as

_supra_) is intensely stimulated. But except in respects such as these

the doctrine of energetics gives a complete synthesis of the course and

relations of the chemical reactions of matter in bulk, from which we can

eliminate atomism altogether by restating the merely numerical atomic

theory of Dalton as a principle of equivalent combining proportions. Of

recent years there has been a considerable school of chemists who insist

on this procedure as a purification of their science from the

hypothetical ideas as to atoms and molecules, in terms of which its

experimental facts have come to be expressed. A complete system of

doctrine can be developed in this manner, but its scope will be limited.

It makes use of one principle of correlation, the doctrine of available

energy, and discards another such principle, the atomic theory. Nor can

it be said that the one principle is really more certain and definite

than the other. This may be illustrated by what has sometimes by German

writers been called Gibbs's paradox: the energy that is available for

mechanical effect in the inter-diffusion of given volumes of two gases

depends only on these volumes and their pressures, and is independent of

what the gases are; if the gases differed only infinitesimally in

constitution it would still be the same, and the question arises where

we are to stop, for we cannot suppose the inter-diffusion of two

identical gases to be a source of power. This then looks like a real

failure, or rather limitation, of the principle; and there are other

such, that can only be satisfactorily explained by aid of the

complementary doctrine of molecular theory. That theory, in fact, shows

that the more nearly identical the gases are, the slower will be the

process of inter-diffusion, so that the mechanical energy will indeed be

available, but only after a time that becomes indefinitely prolonged. It

is a case in which the simple doctrine of energetics becomes inadequate

before the limit is reached. The phenomena of highly rarefied gases

provide other cases. And in fact the only reason hitherto thought of for

the invariable tendency of available energy to diminish, is that it

represents the general principle that in the kinetic play of a vast

assemblage of independent molecules individually beyond our control, the

normal tendency is for the regularities to diminish and the motions to

become less correlated: short of some such reason, it is an unexplained

empirical principle. In the special departments of dynamical physics on

the other hand, the molecular theory, there dynamical and therefore much

more difficult and less definite, is an indispensable part of the

framework of science; and even experimental chemistry now leans more and

more on new physical methods and instruments. Without molecular theory

the clue which has developed into spectrum analysis, bringing with it

stellar chemistry and a new physical astronomy, would not have been

available; nor would the laws of diffusion and conduction in gases have

attained more than an empirical form; nor would it have been possible to

weave the phenomena of electrodynamics and radiation into an entirely

rational theory.

The doctrine of available energy, as the expression of thermodynamic

theory, is directly implied in Carnot's Essai of 1824, and constitutes,

in fact, its main theme; it took a fresh start, in the light of fuller

experimental knowledge regarding the nature of heat, in the early

memoirs of Rankine and Lord Kelvin, which may be found in their

Collected Scientific Papers; a subsequent exposition occurs in Maxwell's

_Theory of Heat_; its most familiar form of statement is Lord Kelvin's

principle of the dissipation of available energy. Its principles were

very early applied by James Thomson to a physico-chemical problem, that

of the influence of stress on the growth of crystals in their mother

liquor. The "thermodynamic function" introduced by Rankine into its

development is the same as the "entropy" of the material system,

independently defined by Clausius about the same time. Clausius's form

of the principle, that in an adiabatic system the entropy tends

continually to increase, has been placed by Professor Willard Gibbs, of

Yale University, at the foundation of his magnificent but complex and

difficult development of the theory. His monumental memoir "On the

Equilibrium of Heterogeneous Substances," first published in _Trans.

Connecticut Academy_ (1876-1878), made a clean sweep of the subject; and

workers in the modern experimental science of physical chemistry have

returned to it again and again to find their empirical principles

forecasted in the light of pure theory, and to derive fresh inspiration

for new departures. As specially preparatory to Gibbs's general

discussion may be mentioned Lord Rayleigh's memoir on the thermodynamics

of gaseous diffusion (_Phil. Mag._, 1876), which was expounded by

Maxwell in the 9th edition of the _Ency. Brit_. (art. DIFFUSION). The

fundamental importance of the doctrine of dissipation of energy for the

theory of chemical reaction had already been insisted on in general

terms by Rayleigh; subsequent to, but independently of, Gibbs's work it

had been elaborated by von Helmholtz (_Gesamm. Abhandl_. ii. and iii.)

in connexion with the thermodynamics of voltaic cells, and more

particularly in the calculation of the free or available energy of

solutions from data of vapour-pressure, with a view to the application

to the theory of concentration cells, therein also coming close to the

doctrine of osmotic pressure. This form of the general theory has here

been traced back substantially to Lord Kelvin under date 1855.

Expositions and developments on various lines will be found in papers by

Riecke and by Planck in _Annalen der Physik_ between 1890 and 1900, in

the course of a memoir by Larmor, Phil. Trans., 1897, A, in Voigt's

_Compendium der Physik_ and his more recent _Thermodynamik_, in Planck's

_Vorlesungen uber Thermodynamik_, in Duhem's elaborate _Traite de

mecanique chimique_ and _Le Potential thermodynamique_, in Whetham's

_Theory of Solution_ and in Bryan's _Thermodynamics_. Numerous

applications to special problems are expounded in van't Hoff's _Lectures

on Theoretical and Physical Chemistry_.

The theory of energetics, which puts a diminishing limit on the amount

of energy available for mechanical purposes, is closely implicated in

the discovery of natural radioactive substances by H. Becquerel, and

their isolation in the very potent form of radium salts by M. and Mme

Curie. The slow degradation of radium has been found by the latter to be

concomitant with an evolution of heat, in amount enormous compared with

other chemical changes. This heat has been shown by E. Rutherford to be

about what must be due to the stoppage of the [alpha] and [beta]

particles, which are emitted from the substance with velocities almost

of the same scale as that of light. If they struck an ideal rigid

target, their lost kinetic energy must all be sent away as radiation;

but when they become entangled among the molecules of actual matter, it

will, to a large extent, be shared among them as heat, with availability

reduced accordingly. In any case the particles that escape into the

surrounding space are so few and their velocity so uniform that we can,

to some extent, treat their energy as directly available mechanically,

in contradistinction to the energy of individual molecules of a gas (cf.

Maxwell's "demons"), e.g. for driving a vane, as in Crookes's experiment

with the cathode rays. Indeed, on account of the high velocity of

projection of the particles from a radium salt, the actions concerned

would find their equilibrium at such enormously high temperatures that

any influence of actually available differences of temperature is not

sensibly a feature of the phenomena. Such actions, however, like

explosive actions in general, are beyond our powers of actual _direct_

measurement as regards the degradation of availability of the energy. It

has been pointed out by Rutherford, R.J. Strutt and others, that the

energy of degradation of even a very minute admixture of active radium

would entirely dominate and mask all other cosmical modes of

transformation of energy; for example, it far outweighs that arising

from the exhaustion of gravitational energy, which has been shown by

Helmholtz and Kelvin to be an ample source for all the activities of our

cosmical system, and to be itself far greater than the energy of any

ordinary chemical rearrangements consequent on a fall of temperature: a

circumstance that makes the existence and properties of this substance

under settled cosmic conditions still more anomalous (see

RADIOACTIVITY). Theoretically it is possible to obtain unlimited

concentration of availability of energy at the expense of an equivalent

amount of degradation spread over a wider field; the potency of electric

furnaces, which have recently opened up a new department of chemistry,

and are limited only by the refractoriness of the materials of which

they are constituted, forms a case in point. In radium we have the very

remarkable phenomenon of far higher concentration occurring naturally in

very minute permanent amounts, so that merely chemical sifting is needed

to produce its aggregation. Even in pitchblende only one molecule in

10^9 seems to be of radium, renewable, however, when lost, by internal

transformation.

The energetics of RADIATION is treated under that heading. See also

THERMODYNAMICS. (J. L.*)

ENERGICI, or ENERGUMENS (Gr. "possessed by a spirit"), the name given in

the early Church to those suffering from different forms of insanity,

who were popularly supposed to be under the control of some indwelling

spirit other than their own. Among primitive races everywhere disease is

explained in this way, and its removal supposed to be effected by

priestly prayers and incantations. They were sometimes called [Greek:

Cheimazomenoi], as being "tossed by the waves" of uncontrollable

impulse. Persons afflicted in this way were restricted from entering the

church, but might share the shelter of the porch with lepers and persons

of offensive life (Hefele, _Conciliengeschichte_, vol. i. S 16). After

the prayers, if quiet, they might come in to receive the bishop's

blessing (_Apost. Const_. viii. 6, 7, 32) and listen to the sermon. They

were daily fed and prayed over by the exorcists, and, in case of

recovery, after a fast of from 20 to 40 days, were admitted to the

eucharist, and their names and cures entered in the church records.

A note on the New Testament use of the word [Greek: energein] and its

cognates will be found in J.A. Robinson's edition of _The Epistle to

the Ephesians_, pp. 241-247; an excursus on "The Conflict with Demons"

in A. Harnack, _The Expansion of Christianity_, i. 152-180. Cf.

EXORCISM.

ENERGY (from the Gr. [Greek: energeia]; [Greek: en], in, [Greek: ergon],

work), in physical science, a term which may be defined as accumulated

mechanical work, which, however, may be only partially available for

use. A bent spring possesses energy, for it is capable of doing work in

returning to its natural form; a charge of gunpowder possesses energy,

for it is capable of doing work in exploding; a Leyden jar charged with

electricity possesses energy, for it is capable of doing work in being

discharged. The motions of bodies, or of the ultimate parts of bodies,

also involve energy, for stopping them would be a source of work.

All kinds of energy are ultimately measured in terms of work. If we

raise 1 lb. of matter through a foot we do a certain amount of work

against the earth's attraction; if we raise 2 lb. through the same

height we do twice this amount of work, and so on. Also, the work done

in raising 1 lb. through 2 ft. will be double of that done in raising it

1 ft. Thus we recognize that the work done varies as the resistance

overcome and the distance through which it is overcome conjointly.

Now, we may select any definite quantity of work we please as our unit,

as, for example, the work done in lifting a pound a foot high from the

sea-level in the latitude of London, which is the unit of work generally

adopted by British engineers, and is called the "foot-pound." The most

appropriate unit for scientific purposes is one which depends only on

the fundamental units of length, mass and time, and is hence called an

absolute unit. Such a unit is independent of gravity or of any other

quantity which varies with the locality. Taking the centimetre, gramme

and second as our fundamental units, the most convenient unit of force

is that which, acting on a gramme for a second, produces in it a

velocity of a centimetre per second; this is called a Dyne. The unit of

work is that which is required to overcome a resistance of a dyne over a

centimetre, and is called an Erg. In the latitude of Paris the dyne is

equal to the weight of about 1/981 of a gramme, and the erg is the

amount of work required to raise 1/981 of a gramme vertically through

one centimetre.

Energy is the capacity for doing work. The unit of energy should

therefore be the same as that of work, and the centimetre-gramme-second

(C.G.S.) unit of energy is the erg.

The forms of energy which are most readily recognized are of course

those in which the energy can be most directly employed in doing

mechanical work; and it is manifest that masses of matter which are

large enough to be seen and handled are more readily dealt with

mechanically than are smaller masses. Hence when useful work can be

obtained from a system by simply connecting visible portions of it by a

train of mechanism, such energy is more readily recognized than is that

which would compel us to control the behaviour of molecules before we

could transform it into useful work. This leads up to the fundamental

distinction, introduced by Lord Kelvin, between "available energy,"

which we can turn to mechanical effect, and "diffuse energy," which is

useless for that purpose.

The conception of work and of energy was originally derived from

observation of purely mechanical phenomena, that is to say, phenomena in

which the relative positions and motions of visible portions of matter

were all that were taken into consideration. Hence it is not surprising

that, in those more subtle forms in which energy cannot be readily or

completely converted into work, the universality of the principle of

energy, its conservation, as regards amount, should for a long while

have escaped recognition after it had become familiar in pure dynamics.

If a pound weight be suspended by a string passing over pulley, in

descending through 10 ft. it is capable of raising nearly a pound weight

attached to the other end of the string, through the same height, and

thus can do nearly 10 foot-pounds of work. The smoother we make the

pulley the more nearly does the amount of useful work which the weight

is capable of doing approach 10 foot-pounds, and if we take into account

the work done against the friction of the pulley, we may say that the

work done by the descending weight is 10 foot-pounds, and hence when the

weight is in its elevated position we have at disposal 10 foot-pounds

more energy than when it is in the lower position. It should be noticed,

however, that this energy is possessed by the system consisting of the

earth and pound together, in virtue of their separation, and that

neither could do work without the other to attract it. The system

consisting of the earth and the pound therefore possesses an amount of

energy which depends on the relative positions of its two parts, on

account of the latent physical connexion existing between them. In most

mechanical systems the working stresses acting between the parts can be

determined when the relative positions of all the parts are known; and

the energy which a system possesses in virtue of the relative positions

of its parts, or its _configuration_, is classified as "potential

energy," to distinguish it from energy of motion which we shall

presently consider. The word potential does not imply that this energy

is not real; it exists in potentiality only in the sense that it is

stored away in some latent manner; but it can be drawn upon without

limit for mechanical work.

It is a fundamental result in dynamics that, if a body be projected

vertically upwards _in vacuo_, with a velocity of v centimetres per

second, it will rise to a height of v^2/2g centimetres, where g

represents the numerical value of the acceleration produced by gravity

in centimetre-second units. Now, if m represent the mass of the body in

grammes its weight will be mg dynes, for it will require a force of mg

dynes to produce in it the acceleration denoted by g. Hence the work

done in raising the mass will be represented by mg.v^2/2g, that is, 1/2

mv^2 _ergs_. Now, whatever be the direction in which a body is moving, a

frictionless constraint, like a string attached to the body, can cause

its velocity to be changed into the vertical direction without any

change taking place in the magnitude of the velocity. Thus it is merely

in virtue of the velocity that the mass is capable of rising against the

resistance of gravity, and hence we recognize that on account of its

motion the body possessed 1/2 mv^2 units of energy. Energy of motion is

usually called "kinetic energy."

A simple example of the transformation of kinetic energy into potential

energy, and vice versa, is afforded by the pendulum. When at the limits

of its swing, the pendulum is for an instant at rest, and all the energy

of the oscillation is static or potential. When passing through its

position of equilibrium, since gravity can do no more work upon it

without changing its fixed point of support, all the energy of

oscillation is kinetic. At intermediate positions the energy is partly

kinetic and partly potential.

Available kinetic energy is possessed by a system of two or more bodies

in virtue of the relative motion of its parts. Since our conception of

velocity is essentially relative, it is plain that any property

possessed by a body in virtue of its motion can be effectively possessed

by it only in relation to those bodies with respect to which it is

moving. If a body whose mass is m grammes be moving with a velocity of v

centimetres per second relative to the earth, the available kinetic

energy possessed by the system is 1/2 mv^2 ergs if m be small relative

to the earth. But if we consider two bodies each of mass m and one of

them moving with velocity v relative to the other, only 1/4 mv^2 units

of work is available from this system alone. Thus the estimation of

kinetic energy is intimately affected by the choice of our base of

measurement.

When the stresses acting between the parts of a system depend _only_ on

the relative positions of those parts, the sum of the kinetic energy and

potential energy of the system is always the same, provided the system

be not acted upon by anything outside it. Such a system is called

"conservative," and is well illustrated by the swinging pendulum above

referred to. But there are stresses which depend on the relative

_motion_ of the visible bodies between which they appear to act. When

work is done against these forces no full equivalent of potential

energy may be produced; this applies especially to frictional forces,

for if the motion of the system be reversed the forces will be also

reversed and will still oppose the motion. It was long believed that

work done against such forces was lost, and it was not till the 19th

century that the energy thus transformed was traced; the conservation of

energy has become the master-key to unlock the connexions in inanimate

nature.

It was pointed out by Thomson (Lord Kelvin) and P.G. Tait that Newton

had divined the principle of the conservation of energy, so far as it

belongs purely to mechanics. But what became of the work done against

friction and such non-conservative forces remained obscure, while the

chemical doctrine that heat was an indestructible substance afterwards

led to the idea that it was lost. There was, however, even before

Newton's time, more than a suspicion that heat was a form of energy.

Francis Bacon expressed his conviction that heat consists of a kind of

motion or "brisk agitation" of the particles of matter. In the _Novum

Organum_, after giving a long list of the sources of heat, he says:

"From these examples, taken collectively as well as singly, the nature

whose limit is heat appears to be motion.... It must not be thought that

heat generates motion or motion heat (though in some respects this is

true), but the very essence of heat, or the substantial self of heat, is

motion and nothing else."

After Newton's time the first vigorous effort to restore the

universality of the doctrine of energy was made by Benjamin Thompson,

Count Rumford, and was published in the _Phil. Trans_. for 1798. Rumford

was engaged in superintending the boring of cannon in the military

arsenal at Munich, and was struck by the amount of heat produced by the

action of the boring bar upon the brass castings. In order to see

whether the heat came out of the chips he compared the capacity for heat

of the chips abraded by the boring bar with that of an equal quantity of

the metal cut from the block by a fine saw, and obtained the same result

in the two cases, from which he concluded that "the heat produced could

not possibly have been furnished at the expense of the latent heat of

the metallic chips."

Rumford then turned up a hollow cylinder which was cast in one piece

with a brass six-pounder, and having reduced the connexion between the

cylinder and cannon to a narrow neck of metal, he caused a blunt borer

to press against the hollow of the cylinder with a force equal to the

weight of about 10,000 lb., while the casting was made to rotate in a

lathe. By this means the mean temperature of the brass was raised

through about 70 deg. Fahr., while the amount of metal abraded was only

837 grains.

In order to be sure that the heat was not due to the action of the air

upon the newly exposed metallic surface, the cylinder and the end of the

boring bar were immersed in 18.77 lb. of water contained in an oak box.

The temperature of the water at the commencement of the experiment was

60 deg. Fahr., and after two horses had turned the lathe for 2-1/2 hours

the water boiled. Taking into account the heat absorbed by the box and

the metal, Rumford calculated that the heat developed was sufficient to

raise 26.58 lb. of water from the freezing to the boiling point, and in

this calculation the heat lost by radiation and conduction was

neglected. Since one horse was capable of doing the work required,

Rumford remarked that one horse can generate heat as rapidly as nine wax

candles burning in the ordinary manner.

Finally, Rumford reviewed all the sources from which the heat might have

been supposed to be derived, and concluded that it was simply produced

by the friction, and that the supply was inexhaustible. "It is hardly

necessary to add," he remarks, "that anything which any insulated body

or system of bodies can continue to furnish _without limitation_ cannot

possibly be a _material substance_; and it appears to me to be extremely

difficult, if not quite impossible, to form any distinct idea of

anything capable of being excited and communicated in the manner that

heat was excited and communicated in these experiments, except it be

_motion_."

About the same time Davy showed that two pieces of ice could be melted

by rubbing them together in a vacuum, although everything surrounding

them was at a temperature below the freezing point. He did not, however,

infer that since the heat could not have been supplied by the ice, for

ice absorbs heat in melting, this experiment afforded conclusive proof

against the substantial nature of heat.

Though we may allow that the results obtained by Rumford and Davy

demonstrate satisfactorily that heat is in some way due to motion, yet

they do not tell us to what particular dynamical quantity heat

corresponds. For example, does the heat generated by friction vary as

the friction and the time during which it acts, or is it proportional to

the friction and the distance through which the rubbing bodies are

displaced--that is, to the work done against friction--or does it

involve any other conditions? If it can be shown that, however the

duration and all other conditions of the experiment may be varied, the

same amount of heat can in the end be always produced when the same

amount of _energy_ is expended, then, and only then, can we infer that

heat is a form of energy, and that the energy consumed has been really

transformed into heat. This was left for J.P. Joule to achieve; his

experiments conclusively prove that heat and energy are of the same

nature, and that all other forms of energy can be transformed into an

equivalent amount of heat.

The quantity of energy which, if entirely converted into heat, is

capable of raising the temperature of the unit mass of water from 0 deg.

C. to 1 deg. C. is called the mechanical equivalent of heat. One of the

first who took in hand the determination of the mechanical equivalent of

heat was Marc. Seguin, a nephew of J.M. Montgolfier. He argued that, if

heat be energy, then, when it is employed in doing work, as in a

steam-engine, some of the heat must itself be consumed in the operation.

Hence he inferred that the amount of heat given up to the condenser of

an engine when the engine is doing work must be less than when the same

amount of steam is blown through the engine without doing any work.

Seguin was unable to verify this experimentally, but in 1857 G.A. Hirn

succeeded, not only in showing that such a difference exists, but in

measuring it, and hence determining a tolerably approximate value of the

mechanical equivalent of heat. In 1839 Seguin endeavoured to determine

the mechanical equivalent of heat from the loss of heat suffered by

steam in expanding, _assuming_ that the whole of the heat so lost was

consumed in doing external work against the pressure to which the steam

was exposed. This assumption, however, cannot be justified, because it

neglected to take account of work which might possibly have to be done

_within the steam itself_ during the expansion.

In 1842 R. Mayer, a physician at Heilbronn, published an attempt to

determine the mechanical equivalent of heat from the heat produced when

air is compressed. Mayer made an assumption the converse of that of

Seguin, asserting that the whole of the work done in compressing the air

was converted into heat, and neglecting the possibility of heat being

consumed in doing work within the air itself or being produced by the

transformation of internal potential energy. Joule afterwards proved

(see below) that Mayer's assumption was in accordance with fact, so that

his method was a sound one as far as experiment was concerned; and it

was only on account of the values of the specific heats of air at

constant pressure and at constant volume employed by him being very

inexact that the value of the mechanical equivalent of heat obtained by

Mayer was very far from the truth.

Passing over L.A. Colding, who in 1843 presented to the Royal Society of

Copenhagen a paper entitled "Theses concerning Force," which clearly

stated the "principle of the perpetuity of energy," and who also

performed a series of experiments for the purpose of determining the

heat developed by the compression of various bodies, which entitle him

to be mentioned among the founders of the modern theory of energy, we

come to Dr James Prescott Joule of Manchester, to whom we are indebted

more than to any other for the establishment of the principle of the

conservation of energy on the broad basis on which it has since stood.

The best-known of Joule's experiments was that in which a brass paddle

consisting of eight arms rotated in a cylindrical vessel of water

containing four fixed vanes, which allowed the passage of the arms of

the paddle but prevented the water from rotating as a whole. The paddle

was driven by weights, and the temperature of the water was observed by

thermometers which could indicate 1/200th of a degree Fahrenheit.

Special experiments were made to determine the work done against

resistances outside the vessel of water, which amounted to about .006 of

the whole, and corrections were made for the loss of heat by radiation,

the buoyancy of the air affecting the descending weights, and the energy

dissipated when the weights struck the floor with a finite velocity.

From these experiments Joule obtained 72.692 foot-pounds in the latitude

of Manchester as equivalent to the amount of heat required to raise 1

lb. of water through 1 deg. Fahr, from the freezing point. Adopting the

centigrade scale, this gives 1390.846 foot-pounds.

With an apparatus similar to the above, but smaller, made of iron and

filled with mercury, Joule obtained results varying from 772.814

foot-pounds when driving weights of about 58 lb. were employed to

775.352 foot-pounds when the driving weights were only about 19-1/2 lb.

By causing two conical surfaces of cast-iron immersed in mercury and

contained in an iron vessel to rub against one another when pressed

together by a lever, Joule obtained 776.045 foot-pounds for the

mechanical equivalent of heat when the heavy weights were used, and

774.93 foot-pounds with the small driving weights. In this experiment a

great noise was produced, corresponding to a loss of energy, and Joule

endeavoured to determine the amount of energy necessary to produce an

equal amount of sound from the string of a violoncello and to apply a

corresponding correction.

The close agreement between the results at least indicates that "the

amount of heat produced by friction is proportional to the work done and

independent of the nature of the rubbing surfaces." Joule inferred from

them that the mechanical equivalent of heat is probably about 772

foot-pounds, or, employing the centigrade scale, about 1390 foot-pounds.

Previous to determining the mechanical equivalent of heat by the most

accurate experimental method at his command, Joule established a series

of cases in which the production of one kind of energy was accompanied

by a disappearance of some other form. In 1840 he showed that when an

electric current was produced by means of a dynamo-magneto-electric

machine the heat generated in the conductor, when no external work was

done by the current, was the same as if the energy employed in producing

the current had been converted into heat by friction, thus showing that

electric currents conform to the principle of the conservation of

energy, since energy can neither be created nor destroyed by them. He

also determined a roughly approximate value for the mechanical

equivalent of heat from the results of these experiments. Extending his

investigations to the currents produced by batteries, he found that the

total voltaic heat generated in any circuit was proportional to the

number of electrochemical equivalents electrolysed in each cell

multiplied by the electromotive force of the battery. Now, we know that

the number of electrochemical equivalents electrolysed is proportional

to the whole amount of electricity which passed through the circuit, and

the product of this by the electromotive force of the battery is the

work done by the latter, so that in this case also Joule showed that the

heat generated was proportional to the work done.

In 1844 and 1845 Joule published a series of researches on the

compression and expansion of air. A metal vessel was placed in a

calorimeter and air forced into it, the amount of energy expended in

compressing the air being measured. Assuming that the whole of the

energy was converted into heat, when the air was subjected to a pressure

of 21.5 atmospheres Joule obtained for the mechanical equivalent of heat

about 824.8 foot-pounds, and when a pressure of only 10.5 atmospheres

was employed the result was 796.9 foot-pounds.

In the next experiment the air was compressed as before, and then

allowed to escape through a long lead tube immersed in the water of a

calorimeter, and finally collected in a bell jar. The amount of heat

absorbed by the air could thus be measured, while the work done by it in

expanding could be readily calculated. In allowing the air to expand

from a pressure of 21 atmospheres to that of 1 atmosphere the value of

the mechanical equivalent of heat obtained was 821.89 foot-pounds.

Between 10 atmospheres and 1 it was 815.875 foot-pounds, and between 23

and 14 atmospheres 761.74 foot-pounds.

But, unlike Mayer and Seguin, Joule was not content with assuming that

when air is compressed or allowed to expand the heat generated or

absorbed is the equivalent of the work done and of that only, no change

being made in the internal energy of the air itself when the temperature

is kept constant. To test this two vessels similar to that used in the

last experiment were placed in the same calorimeter and connected by a

tube with a stop-cock. One contained air at a pressure of 22

atmospheres, while the other was exhausted. On opening the stop-cock no

work was done by the expanding air against external forces, since it

expanded into a vacuum, and it was found that no heat was generated or

absorbed. This showed that Mayer's assumption was true. On repeating the

experiment when the two vessels were placed in different calorimeters,

it was found that heat was absorbed by the vessel containing the

compressed air, while an equal quantity of heat was produced in the

calorimeter containing the exhausted vessel. The heat absorbed was

consumed in giving motion to the issuing stream of air, and was

reproduced by the impact of the particles on the sides of the exhausted

vessel. The subsequent researches of Dr Joule and Lord Kelvin (_Phil.

Trans_., 1853, p. 357, 1854, p. 321, and 1862, p. 579) showed that the

statement that no _internal work_ is done when a gas expands or

contracts is not quite true, but the amount is very small in the cases

of those gases which, like oxygen, hydrogen and nitrogen, can only be

liquefied by intense cold and pressure.

For a long time the final result deduced by Joule by these varied and

careful investigations was accepted as the standard value of the

mechanical equivalent of heat. Recent determinations by H.A. Rowland and

others, necessitated by modern requirements, have shown that it is in

error, but by less than 1%. The writings of Joule, which thus occupy the

place of honour in the practical establishment of the conservation of

energy, have been collected into two volumes published by the Physical

Society of London. On the theoretical side the greatest stimulus came

from the publication in 1847, without knowledge of Mayer or Joule, of

Helmholtz's great memoir, _Uber die Erhaltung der Kraft_, followed

immediately (1848-1852) by the establishment of the science of

thermodynamics (q.v.), mainly by R. Clausius and Lord Kelvin on the

basis of "Carnot's principle" (1824), modified in expression so as to be

consistent with the conservation of energy (see ENERGETICS).

Though we can convert the whole of the energy possessed by any

mechanical system into heat, it is not in our power to perform the

inverse operation, and to utilize the whole of the heat in doing

mechanical work. Thus we see that different forms of energy are not

equally valuable for conversion into work. The ratio of the portion of

the energy of a system which can under given conditions be converted

into mechanical work to the whole amount of energy operated upon may be

called the "availability" of the energy. If a system be removed from all

communication with anything outside of itself, the whole amount of

energy possessed by it will remain constant, but will of its own accord

tend to undergo such transformations as will diminish its availability.

This general law, known as the principle of the "dissipation of energy,"

was first adequately pointed out by Lord Kelvin in 1852; and was applied

by him to some of the principal problems of cosmical physics. Though

controlling all phenomena of which we have any experience, the principle

of the dissipation of energy rests on a very different foundation from

that of the conservation of energy; for while we may conceive of no

means of circumventing the latter principle, it seems that the actions

of intelligent beings are subject to the former only in consequence of

the rudeness of the machinery which they have at their disposal for

controlling the behaviour of those ultimate portions of matter, in

virtue of the motions or positions of which the energy with which they

have to deal exists. If we have a weight capable of falling through a

certain distance, we can employ the mutual forces of the system

consisting of the earth and weight to do an amount of useful work which

is less than the full amount of potential energy possessed by the system

only in consequence of the friction of the constraints, so that the

limit of availability in this case is determined only by the friction

which is unavoidable. Here we have to deal with a transformation with

which we can grapple, and which can be controlled for our purposes. If,

on the other hand, we have to deal with a system of molecules of whose

motions in the aggregate we become conscious only by indirect means,

while we know absolutely nothing either of the motions or positions of

any individual molecule, it is obvious that we cannot grasp single

molecules and control their movements so as to derive the full amount of

work from the system. All we can do in such cases is to place the system

under certain conditions of transformation, and be content with the

amount of work which it is, as it were, willing to render up under those

conditions. Thus the principle of Carnot involves the conclusion that a

greater proportion of the heat possessed by a body at a high temperature

can be converted into work than in the case of an equal quantity of heat

possessed by a body at a low temperature, so that the availability of

heat increases with the temperature.

Clerk Maxwell supposed two compartments, A and B, to be filled with gas

at the same temperature, and to be separated by an ideal, infinitely

thin partition containing a number of exceedingly small trap-doors, each

of which could be opened or closed without any expenditure of energy. An

intelligent creature, or "demon," possessed of unlimited powers of

vision, is placed in charge of each door, with instructions to open the

door whenever a particle in A comes towards it with more than a certain

velocity V, and to keep it closed against all particles in A moving with

less than this velocity, but, on the other hand, to open the door

whenever a particle in B approaches it with less than a certain velocity

v, which is not greater than V, and to keep it closed against all

particles in B moving with a greater velocity than this. By continuing

this process every unit of mass which enters B will carry with it more

energy than each unit which leaves B, and hence the temperature of the

gas in B will be raised and that of the gas in A lowered, while no heat

is lost and no energy expended; so that by the application of

intelligence alone a portion of gas of uniform pressure and temperature

may be sifted into two parts, in which both the temperature and the

pressure are different, and from which, therefore, work can be obtained

at the expense of heat. This shows that the principle of the dissipation

of energy has control over the actions of those agents only whose

faculties are too gross to enable them to grapple individually with the

minute portions of matter which are the seat of energy.

In 1875 Lord Rayleigh published an investigation on "the work which may

be gained during the mixing of gases." In the preface he states the

position that "whenever, then, two gases are allowed to mix without the

performance of work, there is dissipation of energy, and an opportunity

of doing work at the expense of low temperature heat has been for ever

lost." He shows that the amount of work obtainable is equal to that

which can be done by the first gas in expanding into the space occupied

by the second (supposed vacuous) together with that done by the second

in expanding into the space occupied by the first. In the experiment

imagined by Lord Rayleigh a porous diaphragm takes the place of the

partition and trap-doors imagined by Clerk Maxwell, and the molecules

sort themselves automatically on account of the difference in their

average velocities for the two gases. When the pressure on one side of

the diaphragm thus becomes greater than that on the other, work may be

done at the expense of heat in pushing the diaphragm, and the operation

carried on with continual gain of work until the gases are uniformly

diffused. There is this difference, however, between this experiment and

the operation imagined by Maxwell, that when the gases have diffused the

experiment cannot be repeated; and it is no more contrary to the

dissipation of energy than is the fact that work may be derived at the

expense of heat when a gas expands into a vacuum, for the working

substance is not finally restored to its original condition; while

Maxwell's "demons" may operate without limit.

In such experiments the molecular energy of a gas is converted into work

only in virtue of the molecules being separated into classes in which

their velocities are different, and these classes then allowed to act

upon one another through the intervention of a suitable heat-engine.

This sorting can occur spontaneously to a limited extent; while if we

could carry it out as far as we pleased we might transform the whole of

the heat of a body into work. The theoretical availability of heat is

limited only by our power of bringing those particles whose motions

constitute heat in bodies to rest relatively to one another; and we have

precisely similar practical limits to the availability of the energy due

to the motion of visible and tangible bodies, though theoretically we

can then trace all the stages.

If a battery of electromotive force E maintain a current C in a

conductor, and no other electromotive force exist in the circuit, the

whole of the work done will be converted into heat, and the amount of

work done per second will be EC. If R denote the resistance of the whole

circuit, E = CR, and the heat generated per second is C^2R. If the

current drive an electromagnetic engine, the reaction of the engine will

produce an electromotive force opposing the current. Suppose the current

to be thus reduced to C'. Then the work done by the battery per second

will be EC' or CC'R, while the heat generated per second will be C'^2R,

so that we have the difference (C-C')C'R for the energy consumed in

driving the engine. The ratio of this to the whole work done by the

battery is (C-C')/C, so that the efficiency is increased by diminishing

C'. If we could drive the engine so fast as to reduce C' to zero, the

whole of the energy of the battery would be available, no heat being

produced in the wires, but the horse-power of the engine would be

indefinitely small. The reason why the whole of the energy of the

current is not available is that heat must always be generated in a wire

in which a finite current is flowing, so that, in the case of a battery

in which the whole of the energy of chemical affinity is employed in

producing a current, the availability of the energy is limited only on

account of the resistance of the conductors, and may be increased by

diminishing this resistance. The availability of the energy of

electrical separation in a charged Leyden jar is also limited only by

the resistance of conductors, in virtue of which an amount of heat is

necessarily produced, which is greater the less the time occupied in

discharging the jar. The availability of the energy of magnetization is

limited by the coercive force of the magnetized material, in virtue of

which any change in the intensity of magnetization is accompanied by the

production of heat.

In all cases there is a general tendency for other forms of energy to be

transformed into heat on account of the friction of rough surfaces, the

resistance of conductors, or similar causes, and thus to lose

availability. In some cases, as when heat is converted into the kinetic

energy of moving machinery or the potential energy of raised weights,

there is an ascent of energy from the less available form of heat to the

more available form of mechanical energy, but in all cases this is

accompanied by the transfer of other heat from a body at a high

temperature to one at a lower temperature, thus losing availability to

an extent that more than compensates for the rise.

It is practically important to consider the rate at which energy may be

transformed into useful work, or the horse-power of the agent. It

generally happens that to obtain the greatest possible amount of work

from a given supply of energy, and to obtain it at the greatest rate,

are conflicting interests. We have seen that the _efficiency_ of an

electromagnetic engine is greatest when the current is indefinitely

small, and then the rate at which it works is also indefinitely small.

M.H. von Jacobi showed that for a given electromotive force in the

battery the horse-power is greatest when the current is reduced to

one-half of what it would be if the engine were at rest. A similar

condition obtains in the steam-engine, in which a great rate of working

necessitates the dissipation of a large amount of energy.

(W. G.; J. L.*)

ENFANTIN, BARTHELEMY PROSPER (1796-1864), French social reformer, one of

the founders of Saint-Simonism, was born at Paris on the 8th of February

1796. He was the son of a banker of Dauphiny, and after receiving his

early education at a lyceum, was sent in 1813 to the Ecole

Polytechnique. In March 1814 he was one of the band of students who, on

the heights of Montmartre and Saint-Chaumont, attempted resistance to

the armies of the allies then engaged in the investment of Paris. In

consequence of this outbreak of patriotic enthusiasm, the school was

soon after closed by Louis XVIII., and the young student was compelled

to seek some other career instead of that of the soldier. He first

engaged himself to a country wine merchant, for whom he travelled in

Germany, Russia and the Netherlands. In 1821 he entered a banking-house

newly established at St Petersburg, but returned two years later to

Paris, where he was appointed cashier to the Caisse Hypothecaire. At the

same time he became a member of the secret society of the Carbonari. In

1825 a new turn was given to his thoughts and his life by the friendship

which he formed with Olinde Rodriguez, who introduced him to

Saint-Simon. He embraced the new doctrines with ardour, and by 1829 had

become one of the acknowledged heads of the sect (see SAINT-SIMON).

After the Revolution of 1830 Enfantin resigned his office of cashier,

and devoted himself wholly to his cause. Besides contributing to the

_Globe_ newspaper, he made appeals to the people by systematic

preaching, and organized centres of action in some of the principal

cities of France. The headquarters in Paris were removed from the modest

rooms in the Rue Taranne, and established in large halls near the

Boulevard Italien. Enfantin and Bazard (q.v.) were proclaimed "Peres

Supremes." This union of the supreme fathers, however, was only nominal.

A divergence was already manifest, which rapidly increased to serious

difference and dissension. Bazard had devoted himself to political

reform, Enfantin to social and moral change; Bazard was organizer and

governor, Enfantin was teacher and consoler; the former attracted

reverence, the latter love. A hopeless antagonism arose between them,

which was widened by Enfantin's announcement of his theory of the

relation of man and woman, which would substitute for the "tyranny of

marriage" a system of "free love." Bazard now separated from his

colleague, and in his withdrawal was followed by all those whose chief

aim was philosophical and political. Enfantin thus became sole "father,"

and the few who were chiefly attracted by his religious pretensions and

aims still adhered to him. New converts joined them, and Enfantin

assumed that his followers in France numbered 40,000. He wore on his

breast a badge with his title of "Pere," was spoken of by his preachers

as "the living law," declared, and probably believed, himself to be the

chosen of God, and sent out emissaries in a quest of a woman predestined

to be the "female Messiah," and the mother of a new Saviour. The quest

was very costly and altogether fruitless. No such woman was

discoverable. Meanwhile believers in Enfantin and his new religion were

multiplying in all parts of Europe. His extravagances and success at

length brought down upon him the hand of the law. Public morality was in

peril, and in May 1832 the halls of the new sect were closed by the

government, and the father, with some of his followers, appeared before

the tribunals. He now retired to his estate at Menilmontant, near Paris,

where with forty disciples, all of them men, he continued to carry out

his socialistic views. In August of the same year he was again arrested,

and on his appearance in court he desired his defence to be undertaken

by two women who were with him, alleging that the matter was of special

concern to women. This was of course refused. The trial occupied two

days and resulted in a verdict of guilty, and a sentence of imprisonment

for a year with a small fine.

This prosecution finally discredited the new society. Enfantin was

released in a few months, and then, accompanied by some of his

followers, he went to Egypt. He stayed there two years, and might have

entered the service of the viceroy if he would have professed himself,

as a few of his friends did, a Mahommedan. On his return to France, a

sadder and practically a wiser man, he settled down to very prosaic

work. He became first a postmaster near Lyons, and in 1841 was

appointed, through the influence of some of his friends who had risen to

posts of power, member of a scientific commission on Algeria, which led

him to engage in researches concerning North Africa and colonization in

general. in 1845 he was appointed a director of the Paris & Lyons

railway. Three years later he established, in conjunction with

Duveyrier, a daily journal, entitled _Le Credit_, which was discontinued

in 1850. He was afterwards attached to the administration of the railway

from Lyons to the Mediterranean. Father Enfantin held fast by his ideal

to the end, but he had renounced the hope of giving it a local

habitation and a name in the degenerate obstinate world. His personal

influence over those who associated with him was immense. "He was a man

of a noble presence, with finely formed and expressive features. He was

gentle and insinuating in manner, and possessed a calm, graceful and

winning delivery" (_Gent. Mag_., Jan. 1865). His evident sincerity, his

genuine enthusiasm, gave him his marvellous ascendancy. Not a few of his

disciples ranked afterwards amongst the most distinguished men of

France. He died suddenly at Paris on the 1st of September 1864.

Amongst his works are--Doctrine de Saint-Simon (written in conjunction

with several of his followers), published in 1830, and several times

republished; _Economie politique et politique Saint-Simonienne_

(1831); _Correspondance politique_ (1835-1840); _Corresp. philos. et

religieuse_ (1843-1845); and _La Vie eternelle passee, presente,

future_ (1861). A large number of articles by his hand appeared in _Le

Producteur, L'Organisateur, Le Globe,_ and other periodicals. He also

wrote in 1832 _Le Livre nouveau_, intended as a substitute for the

Christian Scriptures, but it was not published.

See G. Weill, _L'Ecole Saint-Simonienne, son histoire, son influence,

jusqu' a nos jours_ (Paris, 1896).

ENFIDAVILLE [_Dar-el-Bey_], a town of Tunisia, on the railway between

Tunis and Susa, 30 m. N.E. of the last-named place and 5 m. inland from

the Gulf of Hammamet. Enfidaville is the chief settlement on the Enfida

estate, a property of over 300,000 acres in the Sahel district of

Tunisia, forming a rectangle between the towns of Hammamet, Susa,

Kairawan and Zaghwan. On this estate, devoted to the cultivation of

cereals, olives, vines and to pasturage, are colonies of Europeans and

natives. At Enfidaville, where was, as its native name indicates, a

palace of the beys of Tunis, there is a large horse-breeding

establishment and a much-frequented weekly market. About 5 m. N. of

Enfidaville is Henshir Fraga (anc. _Uppenna_), where are ruins of a

large fortress and of a church in which were found mosaics with epitaphs

of various bishops and martyrs.

The Enfida estate was granted by the bey Mahommed-es-Sadok to his chief

minister Khaireddin Pasha (q.v.) in return for the confirmation by the

sultan of Turkey in 1871, through the instrumentality of the pasha, of

the right of succession to the beylik of members of Es-Sadok's family.

When, some years later, Khaireddin left Tunisia for Constantinople he

sold the estate to a Marseilles company, which resold it to the Societe

Franco-africaine.

ENFIELD, a township of Hartford county, Connecticut, U.S.A., in the N.

part of the state, on the E. bank of the Connecticut river, 20 m. N. of

Hartford. It has an area of 35 sq. m., with three villages--Thompsonville,

Hazardville and Enfield. Pop. (1890) 7199; (1900) 6699 (1812

foreign-born); (1910) 9719. Its principal manufactures are gunpowder,

carpets, brick, cotton press machinery, and coffin hardware. In Enfield

and its vicinity much tobacco is grown. First settled in 1679, Enfield was

a part of the township of Springfield, Massachusetts, until 1683, when it

was made a separate township; in 1749 it became a part of Connecticut. At

a town meeting on the 11th of July 1774 it was resolved that "a firm and

inviolable union of our colonies is absolutely necessary for the defence

of our civil rights," and that "the most effectual measures to defeat the

machinations of the enemies of His Majesty's government and the liberties

of America is to break off all commercial intercourse with Great Britain

and the West Indies until these oppressive acts for raising a revenue in

America are repealed." A Shaker community was established in the township

in 1781, at what is now called Shaker Station.

See Francis Olcutt Allen, _History of Enfield_ (Lancaster, Pa., 1900).

ENFIELD, a market town in the Enfield parliamentary division of

Middlesex, England, 11 m. N. of London Bridge, on the Great Northern and

Great Eastern railways. Pop. of urban district, (1891) 31,536, (1901)

42,738. It is picturesquely situated on the western slope of the Lea

valley, with a considerable extension towards the river, mainly

consisting of artisans' dwellings (Churchbury, Ponder's End, and Enfield

Highway on the Old North Road). Great numbers of villas occupied by

those whose work lies in London have grown up; and many of the

inhabitants are employed in the Royal Small Arms factory at Enfield

Lock. The church of St Andrew is mainly Perpendicular, but has Early

English portions; it contains several ancient monuments and brasses, and

flanks the market-place, with its modern cross. Enfield Palace fronts

the High Street; it retains portions of the building of Edward VI., but

has been greatly altered. The grammer school, near the church, was

founded in 1557. The New River flows through the parish, and Sir Hugh

Myddleton, its projector, was for some time resident here. Middleton

House, named after him, is one of several fine mansions in the vicinity.

Of these, Forty Hall, in splendidly timbered grounds, is from the

designs of Inigo Jones; and a former mansion occupying the site of White

Webbs House was suspected as the scene of the hatching of Gunpowder

Plot. The parish is of great extent (12,653 acres).

An Anglo-Saxon derivation, signifying "forest clearing," is indicated

for the name. Enfield Chase was a royal preserve, disafforested in 1777.

The principal manor of Enfield, which was held by Asgar, Edward the

Confessor's master of horse, was in the hands of the Norman baron

Geoffrey de Mandeville at the time of Domesday, and belonged to the

Bohun family in the 12th and 13th centuries. It came, by succession and

marriage, into the possession of the crown under Henry IV., and was

included in the duchy of Lancaster. There were, however, seven other

manors, and of these one, Worcesters, came to the crown in the time of

Henry VIII., whose children resided at the manor-house, Elsynge Hall.

Edward VI., settling both manors upon the princess Elizabeth, rebuilt

Enfield Palace for her. She was a frequent resident here not only before

but after her accession to the throne. About 1664 the palace was

occupied as a school by Robert Uvedale (1642-1722), who was also an

eminent horticulturist, planted the magnificent cedar still standing in

the palace grounds, and formed a herbarium now in the Sloane collection

at the British Museum. The town received grants of markets from Edward

I. and James I.

ENFILADE (a French word, from _enfiler_, to thread, and so to pass

through from end to end), a military term used to express the direction

of fire along an enemy's line, or parapet. This species of fire is most

demoralizing and destructive, since, from its direction, very few guns

or rifles can be brought to bear to meet it. If any considerable body of

men changes front, it immediately lays itself open to enfilade from the

enemy whom it originally faced. Against entrenchments, or the parapets

of fortifications, enfilade is still more effective, as the enemy is

deprived of the protection given by his works and is no better covered

than if he were in the open. Banks of earth, built perpendicular to the

line of defence (called _traverses_), are usually employed to protect

parapets or trenches against enfilade.

ENGADINE (Ger. _Engadin_; Ital. _Engadina_; Ladin, _Engiadina_), the

name of the upper or Swiss portion of the valley of the Inn, which forms

part of the Swiss canton of the Grisons. Its length by carriage road

from the Maloja plateau (5935 ft.) at its south-western end to

Martinsbruck (3406 ft.) at its north-eastern extremity is about 59 m. It

is to be noted that up to and including St Moritz (6037 ft., the

highest) all the villages (save Sils-Baseglia) at its south-western end

are higher than the Maloja plateau itself. The uppermost portion of the

valley contains several lakes, which, as one descends, gradually

diminish in size, those of Sils, Silvaplana and St Moritz. But both the

Maloja plateau and the south-western half of the lake of Sils belong to

the commune of Stampa in the Val Bregaglia, and are included in the

Bregaglia administrative district, so that, from a political point of

view, Sils is the first village that is included in the Engadine. The

rest of the Engadine forms the districts of the Upper Engadine with

eleven communes, and of the Inn (i.e. the Lower Engadine), subdivided

into the Ob Tasna, Remus, and Unter Tasna circles, and containing twelve

communes.

In 1900 the total population of the Engadine was 11,712, of whom 5429

were in the Upper Engadine and 6283 in the Lower Engadine. In point of

religion 8594 were Protestants (4923 in the Lower Engadine and 3671 in

the Upper Engadine), and 3086 Romanists (1728 in the Upper Engadine and

1358 in the Lower Engadine), while there were 12 Jews in the Upper

Engadine and 2 in the Lower Engadine: in the Upper Engadine the majority

in each commune was Protestant (the Romanists strongest in St Moritz),

as also in the case of the Lower Engadine, save Tarasp and Samnaun,

where the Romanists prevail. In point of language 7609 inhabitants (5010

in the Lower Engadine and 2599 in the Upper Engadine) spoke the curious

Ladin dialect (a survival of a primitive Romance tongue), and 2221

German (1265 in the Upper Engadine and 956 in the Lower Engadine). The

capital of the Upper Engadine is Samaden (967 inhabitants), and that of

the Lower Engadine, Schuls (1117 inhabitants). In 1908 there were no

railways in the Engadine, save about 8 m. (from the mouth of the tunnel

past Bevers and Samaden to St Moritz village) of the railway pierced

(1898-1902) beneath (5987 ft.) the Albula Pass (7595 ft.), which now

affords the easiest means of access from Coire to St Moritz (56 m.); but

many railways in and to the Engadine have been planned. The valley is

reached by many passes (over which excellent carriage roads were

constructed 1820-1872). The Maloja (5935 ft.) is the route from

Chiavenna and the Lake of Como to the Upper Engadine, which is also

reached from Coire by the Julier (7504 ft.) and the Albula Passes (7595

ft.) as well as from Tirano in the Valtellina by the Bernina Pass (7645

ft.). On the other hand, the Lower Engadine is accessible from Davos

over the Fluela Pass (7838 ft.) and from Mals at the head of the Adige

valley (or the Vintschgau) by the Ofen Pass (7071 ft.), while from

Martinsbruck, the last Swiss village, a carriage road leads up to

Nauders (5 m.), whence it is 27 m. by road down the Inn valley to

Landeck on the Arlberg railway, or 17-1/2 m. over the Reschen Scheideck

Pass (4902 ft.) to Mals in the Vintschgau.

The Upper Engadine consists of a long, straight, nearly level trough of

26 m., varying from a mile to half a mile in breadth, through which

flows the Inn. On the south-east this trough is limited by the lofty

glacier-clad Bernina group (culminating in the Piz Bernina, 13,304 ft.)

and the range rising between the Inn valley and that of Livigno to the

south-east, while on the north-west the boundary is the extensive Albula

group (culminating in Piz Kesch, 11,228 ft.). The Lower Engadine is far

more picturesque and romantic than the Upper Engadine, the Inn valley

being here much narrower and the fall greater. On its north-west rises

the last bit of the Albula group (culminating in Piz Vadret, 10,584

ft.), and on the north the Silvretta group (culminating in Piz Linard,

11,201 ft.), while to the east and south are the ranges on either side

of the Ofen Pass (culminating in Piz Sesvenna, 10,568 ft.). In the Upper

Engadine the villages are on the floor of the valley, but in the Lower

Engadine many are perched high above the bed of the river on terraces,

and are cut off from each other by deep ravines.

The Upper Engadine is far better known to foreign visitors than the

Lower Engadine, and is consequently much richer and more prosperous. The

mineral waters of St Moritz (q.v.) were known and employed in the 16th

century, and long formed the great attraction of the region. But about

the middle of the 19th century the Upper Engadine came into fashion as a

great "air-cure," and now Maloja, Sils, Silvaplana, Campfer and St

Moritz are all well known; those who desire to explore the glaciers of

the Bernina group mostly resort to Pontresina, on the Flatzbach, the

stream descending from the Bernina Pass. Yet, owing to its great

elevation, the scenery of the Upper Engadine has a bleak, northern

aspect. Pines and larches alone flourish, garden vegetables are grown

only in sunny spots, and there is no tillage. The Alpine flora is very

rich and varied. But snow falls even in August, and the climate is well

described in the proverb, "nine months winter, and three months cold

weather." The villages are built entirely of stone (as also in the Lower

Engadine), chiefly to guard against destructive fires that were formerly

frequent in this narrow, wind-swept valley. The wealth of the

inhabitants consists in their hay meadows and pastures. The lower

pastures support large herds of cows, while the higher are let out (in

both parts of the valley) to Bergamasque shepherds, who come thither

every summer with their flocks. In the Lower Engadine the chief

attraction is formed by the mineral springs at Schuls below Tarasp,

which are much frequented during the summer. The wild gorge of

Finstermunz separates the last Swiss village, Martinsbruck, from the

first Tirolese village, Pfunds, the gorge being passable only on foot,

while the carriage road makes a great detour by way of Nauders, so that

the two villages named are 13 m. by road from each other. The earliest

full description of the country by an English traveller is that by

Archdeacon W. Coxe, in _Travels in Switzerland_ (London, 1789).

The Upper Engadine is not mentioned in authentic documents till 1139,

the bishop of Coire being then the great lord, and, from the 13th

century, having as his bailiffs the family of Planta, the original seat

of which was at Zuz. The valley obtained its freedom from both in 1486

(Planta) and in 1526, when the temporal powers of the bishop were

abolished. In 1367 it (as well as the bishop's vassals in the Lower

Engadine) joined the newly founded League of God's House or

_Gotteshausbund_ (see GRISONS), one of the 3 Raetian Leagues, which

lasted till 1799-1801, when the whole Engadine became part of Canton

Raetia of the Helvetic Republic, which, in 1803, altered its name to

that of Grisons or Graubunden, and then first entered the Swiss

Confederation. In the Upper Engadine the "Referendum" existed as between

the different villages composing a bailiwick (_Hochgericht_). The

history of the Lower Engadine is for long quite different. Though always

comprised in the diocese of Coire, it formed from the early 9th century

onwards (with the Vintschgau) a separate county, which was gradually

absorbed in that which, later, took the name of the county of Tirol. The

limit between the Upper Engadine and the Tirolese Lower Engadine was

definitively fixed in 1282 at the Punt' Ota (the high bridge) just above

Brail, and mentioned in 1139 already. In 1363 Tirol came into the

possession of the Habsburgers, who were troublesome neighbours both to

the Upper Engadine and to the League of God's House. Their power was

stemmed in 1499 at the battle of the Calven gorge (above Mals), though

it was only in 1652 that the Lower Engadine bought up the remaining

rights of the Habsburgers. But the castle of Tarasp (acquired by them in

1464) was excepted: the lordship was given by them in 1687 to the

Dietrichstein family, and held by it till 1801, when Austria ceded it to

France, which, in 1803, handed it over to the Swiss Confederation, by

which it was incorporated in 1809 with the Canton of the Grisons. This

long connexion with Tirol accounts for the fact that Tarasp is still

mainly Romanist, while the lonely Swiss valley of Samnaun (above

Martinsbruck) has given up its Protestantism and its Ladin speech owing

to communications with Tirol being easier than with Switzerland. The

bears in the bear pit at Bern come from the forests in the lower Spol

valley, above Zernez, in the Lower Engadine, on the way to the Ofen

Pass. The upper Spol valley (Livigno) is Italian (see VALTELLINA).

AUTHORITIES.--M. Caviezel, _Das Oberengadin_, 7th edition (Coire,

1896); C. Decurtius, _Ratoromanische Chrestomathie_, vols. v.-ix.

(Erlangen, 1899-1908), deals with the two divisions of the Engadine

from the 16th century to modern times; Mrs H. Freshfield, _A Summer

Tour in the Grisons and the Italian Valleys of the Bernina_ (London,

1862); E. Imhof, _Itinerarium des S.A.C. fur die Albulagruppe_ (Bern,

1893), and _Itinerarium des S.A.C. fur die Silvretta- und

Ofenpassgruppe_ (Mountains of the Lower Engadine) (Bern, 1898); E.

Lechner, _Das Oberengadin in der Vergangenheit und Gegenwart_

(Leipzig, 1900); A. Lorria and E.A. Martel, _Le Massif de la Bernina_

(complete monograph on the Upper Engadine, with full bibliography)

(Zurich, 1894); P.C. von Planta, _Die Curratischen Herrschaften in der

Feudalzeit_ (Bern, 1881); Z. and E. Pallioppi, _Dizionari dels Idioms

Romauntschs d'Engiadina ota e bassa_, &c. (Samaden, 1895); F. de B.

Strickland, _The Engadine_, 2nd edition (London and Samaden, 1891); J.

Ulrich, _Ratoromanische Chrestomathie_, vol. ii. (Halle, 1882).

(W. A. B. C.)

ENGAGED COLUMN, in architecture, a form of column, sometimes defined as

semi or three-quarter detached according to its projection; the term

implies that the column is partly attached to a pier or wall. It is

rarely found in Greek work, and then only in exceptional cases, but it

exists in profusion in Roman architecture. In the temples it is attached

to the cella walls. repeating the columns of the peristyle, and in the

theatres and amphitheatres, where they subdivided the arched openings:

in all these cases engaged columns are utilized as a decorative feature,

and as a rule the same proportions are maintained as if they had been

isolated columns. In Romanesque work the classic proportions are no

longer adhered to; the engaged column, attached to the piers, has always

a special function to perform, either to support subsidiary arches, or,

raised to the vault, to carry its transverse or diagonal ribs. The same

constructional object is followed in the earlier Gothic styles, in which

they become merged into the mouldings. Being virtually always ready

made, so far as their design is concerned, they were much affected by

the Italian revivalists.

ENGEL, ERNST (1821-1896), German political economist and statistician,

was born in Dresden on the 21st of March 1821. He studied at the famous

mining academy of Freiberg, in Saxony, and on completing his curriculum

travelled in Germany and France. Immediately after the revolution of

1848 he was attached to the royal commission in Saxony appointed to

determine the relations between trade and labour. In 1850 he was

directed by the government to assist in the organization of the German

Industrial Exhibition of Leipzig (the first of its kind). The success

which crowned his efforts was so great that in 1854 he was induced to

enter the government service, as chief of the newly instituted

statistical department. He retired, however, from the office in 1858. He

founded at Dresden the first Mortgage Insurance Society

(Hypotheken-Versicherungsgesellschaft), and as a result of the success

of his work was summoned in 1860 to Berlin as director of the

statistical department, in succession to Karl Friedrich Wilhelm

Dieterici (1790-1859). In his new office he made himself a name of

world-wide reputation. Raised to the rank of _Geheimer Regierungsrat_,

he retired in 1882 and lived henceforward in Radebeul near Dresden,

where he died on the 8th of December 1896. Engel was a voluminous writer

on the subjects with which his name is connected, but his statistical

papers are mostly published in the periodicals which he himself

established, viz. _Preuss. Statistik_ (in 1861); _Zeitschrift des

Statistischen Bureaus_, and _Zeitschrift des Statistischen Bureaus des

Konigreichs Sachsen_.

ENGEL, JOHANN JAKOB (1741-1802), German author, was born at Parchim, in

Mecklenburg, on the 11th of September 1741. He studied theology at

Rostock and Butzow, and philosophy at Leipzig, where he took his

doctor's degree. In 1776 he was appointed professor of moral philosophy

and belles-lettres in the Joachimstal gymnasium at Berlin, and a few

years later he became tutor to the crown prince of Prussia, afterwards

Frederick William III. The lessons which he gave his royal pupil in

ethics and politics were published in 1798 under the title

_Furstenspiegel_, and are a favourable specimen of his powers as a

popular philosophical writer. In 1787 he was admitted a member of the

Academy of Sciences of Berlin, and in the same year he became director

of the royal theatre, an office he resigned in 1794. He died on the 28th

of June 1802.

Besides numerous dramas, some of which had a considerable success, Engel

wrote several valuable books on aesthetic subjects. His _Anfangsgrunde

einer Theorie der Dichtungsarten_ (1783) showed fine taste and acute

critical faculty if it lacked imagination and poetic insight. The same

excellences and the same defects were apparent in his _Ideen zu einer

Mimik_ (1785), written in the form of letters. His most popular work was

_Der Philosoph fur die Welt_ (1775), which consists chiefly of dialogues

on men and morals, written from the utilitarian standpoint of the

philosophy of the day. His last work, a romance entitled _Herr Lorenz

Stark_ (1795), achieved a great success, by virtue of the marked

individuality of its characters and its appeal to middle-class

sentiment.

Engel's _Samtliche Schriften_ were published in 12 volumes at Berlin

in 1801-1806; a new edition appeared at Frankfort in 1851. See K.

Schroder, _Johann Jakob Engel_ (Vortrag) (1897).

ENGELBERG, an Alpine village and valley in central Switzerland, much

frequented by visitors in summer and to some extent in winter. It is 14

m. by electric railway from Stansstad, on the Lake of Lucerne, past

Stans. The village (3343 ft.) is in a mountain basin, shut in on all

sides by lofty mountains (the highest is the Titlis, 10,627 ft. in the

south-east), so that it is often hot in summer. It communicates by the

Surenen Pass (7563 ft.) with Wassen, on the St Gotthard railway, and by

the Joch Pass (7267 ft.) past the favourite summer resort of the

Engstlen Alp (6034 ft.), with Meiringen in the Bernese Oberland. The

village has clustered round the great Benedictine monastery which gives

its name to the valley, from the legend that its site was fixed by

angels, so that the spot was named "Mons Angelorum." The monastery was

founded about 1120 and still survives, though the buildings date only

from the early 18th century. Its library suffered much at the hands of

the French in 1798. From 1462 onwards it was under the protectorate of

Lucerne, Schwyz, Unterwalden and Uri. In 1798 the abbot lost all his

temporal powers, and his domains were annexed to the Obwalden division

of Unterwalden, but in 1803 were transferred to the Nidwalden division.

However, in 1816, in consequence of the desperate resistance made by the

Nidwalden men to the new Federal Pact of 1815, they were punished by the

fresh transfer of the valley to Obwalden, part of which it still forms.

As the pastures forming the upper portion of the Engelberg valley have

for ages belonged to Uri, the actual valley itself is politically

isolated between Uri and Nidwalden. The monastery is still directly

dependent on the pope. In 1900 the valley had 1973 inhabitants,

practically all German-speaking and Romanists. (W. A. B. C.)

ENGELBRECHTSDATTER, DORTHE (1634-1716), Norwegian poet, was born at

Bergen on the 16th of January 1634; her father, Engelbrecht Jorgensen,

was originally rector of the high school in that city, and afterwards

dean of the cathedral. In 1652 she married Ambrosius Hardenbech, a

theological writer famous for his flowery funeral sermons, who succeeded

her father at the cathedral in 1659. They had five sons and four

daughters. In 1678 her first volume appeared, _Sjaelens aandelige

Sangoffer_ ("The Soul's Spiritual Offering of Song") published at

Copenhagen. This volume of hymns and devotional pieces, very modestly

brought out, had an unparalleled success. The fortunate poetess was

invited to Denmark, and on her arrival at Copenhagen was presented at

Court. She was also introduced to Thomas Kingo, the father of Danish

poetry, and the two greeted one another with improvised couplets, which

have been preserved, and of which the poetess's reply is incomparably

the neater. In 1683 her husband died, and before 1698 she had buried all

her nine children. In the midst of her troubles appeared her second

work, the _Taareoffer_ ("Sacrifice of Tears"), which is a continuous

religious poem in four books. This was combined with the Sangoffer, and

no fewer than three editions of the united works were published before

her death, and many after it. In 1698 she brought out a third volume of

sacred verse, _Et kristeligt Valet fra Verden_ ("A Christian Farewell to

the World"), a very tame production. She died on the 19th of February

1716. The first verses of Dorthe Engelbrechtsdatter are the best; her

_Sangoffer_ was dedicated to Jesus, the Taareoffer to Queen Charlotte

Amalia; this is significant of her changed position in the eyes of the

world.

ENGELHARDT, JOHANN GEORG VEIT (1791-1855), German theologian, was born

at Neustadt-on-the-Aisch on the 12th of November 1791, and was educated

at Erlangen, where he afterwards taught in the gymnasium (1817), and

became professor of theology in the university (1821). His two great

works were a _Handbuch der Kirchengeschichte_ in 4 vols. (1833-1834),

and a _Dogmengeschichte_ in 2 vols. (1839). He died at Erlangen on the

13th of September 1855.

ENGHIEN, LOUIS ANTOINE HENRI DE BOURBON CONDE, DUC D' (1772-1804), was

the only son of Henri Louis Joseph, prince of Conde, and of Louise Marie

Therese Mathilde, sister of the duke of Orleans (Philippe Egalite), and

was born at Chantilly on the 2nd of August 1772. He was educated

privately by the abbe Millot, and received a military training from the

commodore de Virieux. He early showed the warlike spirit of the house of

Conde, and began his military career in 1788. On the outbreak of the

French Revolution he "emigrated" with very many of the nobles a few days

after the fall of the Bastille, and remained in exile, seeking to raise

forces for the invasion of France and the restoration of the old

monarchy. In 1792, on the outbreak of war, he held a command in the

force of _emigres_ (styled the "French royal army") which shared in the

duke of Brunswick's unsuccessful invasion of France. He continued to

serve under his father and grandfather in what was known as the Conde

army, and on several occasions distinguished himself by his bravery and

ardour in the vanguard. On the dissolution of that force after the peace

of Luneville (February 1801) he married privately the princess

Charlotte, niece of Cardinal de Rohan, and took up his residence at

Ettenheim in Baden, near the Rhine. Early in the year 1804 Napoleon,

then First Consul of France, heard news which seemed to connect the

young duke with the Cadoudal-Pichegru conspiracy then being tracked by

the French police. The news ran that the duke was in company with

Dumouriez and made secret journeys into France. This was false; the

acquaintance was Thumery, a harmless old man, and the duke had no

dealings with Cadoudal or Pichegru. Napoleon gave orders for the seizure

of the duke. French mounted gendarmes crossed the Rhine secretly,

surrounded his house and brought him to Strassburg (15th of March 1804),

and thence to the castle of Vincennes, near Paris. There a commission of

French colonels was hastily gathered to try him. Meanwhile Napoleon had

found out the true facts of the case, and the ground of the accusation

was hastily changed. The duke was now charged chiefly with bearing arms

against France in the late war, and with intending to take part in the

new coalition then proposed against France. The colonels hastily and

most informally drew up the act of condemnation, being incited thereto

by orders from Savary (q.v.), who had come charged with instructions.

Savary intervened to prevent all chance of an interview between the

condemned and the First Consul; and the duke was shot in the moat of the

castle, near a grave which had already been prepared. With him ended the

house of Conde. In 1816 the bones were exhumed and placed in the chapel

of the castle. It is now known that Josephine and Mme de Remusat had

begged Napoleon for mercy towards the duke; but nothing would bend his

will. The blame which the apologists of the emperor have thrown on

Talleyrand or Savary is undeserved. On his way to St Helena and at

Longwood he asserted that, in the same circumstances, he would do the

same again; he inserted a similar declaration in his will.

See H. Welschinger, _Le Due d'Enghien 1772-1804_ (Paris, 1888); A.

Nougaret de Fayet, _Recherches historiques sur le proces et la

condamnation du duc d'Enghien_, 2 vols. (Paris, 1844); Comte A. Boulay

de la Meurthe, _Les Dernieres Annees du due d'Enghien 1801-1804_

(Paris, 1886). For documents see _La Catastrophe du duc d'Enghien_ in

the edition of _Memoires_ edited by M.F. Barriere, also the edition of

the duke's letters, &c., by Count Boulay de la Meurthe (tome i.,

Paris, 1904; tome ii., 1908). (J. Hl. R.)

ENGHIEN, a town in the province of Hainaut, Belgium, lying south of

Grammont. Pop. (1904) 4541. It is the centre of considerable lace, linen

and cotton industries. There is a fine park outside the town belonging

to the duke of Arenberg, whose ancestor, Charles de Ligne, bought it

from Henry IV. in 1607, but the chateau in which the duke of Arenberg of

the 18th century entertained Voltaire no longer exists. Curiously enough

the cottage, a stone building, built by the same duke for Jean Jacques

Rousseau, still stands in the park, while the ducal residence was burnt

down by the _sans-culottes_. A fine pavilion or kiosk, named de

l'Etoile, has also survived. The great Conde was given, for a victory

gained near this place, the right to use the style of Enghien among his

subsidiary titles.

ENGINE (Lat. _ingenium_), a term which in the time of Chaucer had the

meaning of "natural talent" or "ability," corresponding to the Latin

from which it is derived (cf. "A man hath sapiences thre, Memorie,

engin, and intellect also," _Second Nun's Tale_, 339); in this sense it

is now obsolete. It also denoted a mechanical tool or contrivance, and

especially a weapon of war; this use may be compared with that of

_ingenium_ in classical Latin to mean a clever idea or device, and in

later Latin, as in Tertullian, for a warlike instrument or machine. In

the 19th century it came to have, when employed alone, a specific

reference to the steam-engine (q.v.), but it is also used of other prime

movers such as the air-engine, gas-engine and oil-engine (qq.v.).

ENGINEERING, a term for the action of the verb "to engineer," which in

its early uses referred specially to the operations of those who

constructed engines of war and executed works intended to serve military

purposes. Such military engineers were long the only ones to whom the

title was applied. But about the middle of the 18th century there began

to arise a new class of engineers who concerned themselves with works

which, though they might be in some cases, as in the making of roads, of

the same character as those undertaken by military engineers, were

neither exclusively military in purpose nor executed by soldiers, and

those men by way of distinction came to be known as civil engineers. No

better definition of their aims and functions can be given than that

which is contained in the charter (dated 1828) of the Institution of

Civil Engineers (London), where civil engineering is described as the

"art of directing the great sources of power in nature for the use and

convenience of man, as the means of production and of traffic in states,

both for external and internal trade, as applied in the construction of

roads, bridges, aqueducts, canals, river navigation and docks for

internal intercourse and exchange, and in the construction of ports,

harbours, moles, breakwaters and lighthouses, and in the art of

navigation by artificial power for the purposes of commerce, and in the

construction and adaptation of machinery, and in the drainage of cities

and towns." Wide as is this enumeration, the practice of a civil

engineer in the earlier part of the 19th century might cover many or

even most of the subjects it contains. But gradually specialization set

in. Perhaps the first branch to be recognized as separate was

_mechanical_ engineering, which is concerned with steam-engines, machine

tools, mill-work and moving machinery in general, and it was soon

followed by _mining_ engineering, which deals with the location and

working of coal, ore and other minerals. Subsequently numerous other

more or less strictly defined groups and subdivisions came into

existence, such as _naval architecture_ dealing with the design of

ships, _marine_ engineering with the engines for propelling steamers,

_sanitary_ engineering with water-supply and disposal of sewage and

other refuse, _gas_ engineering with the manufacture and distribution of

illuminating gas, and chemical engineering with the design and erection

of the plant required for the manufacture of such chemical products as

alkali, acids and dyes, and for the working of a wide range of

industrial processes. The last great new branch is _electrical_

engineering, which touches on the older branches at so many points that

it has been said that all engineers must be electricians.

ENGINEERS, MILITARY. From the earliest times engineers have been

employed both in the field of war and on field defences. In modern

times, however, the application of numerous scientific and engineering

devices to warfare has resulted in the creation of many minor branches

of military engineering, some of them almost rivalling in importance

their primary duty of fortification and siegecraft, such as the field

telegraph, the balloon service, nearly all demolitions, the building of

pontoon and other bridges, and the construction and working of military

roads, railways, piers, &c. All these branches requiring special

knowledge, the modern tendency is to divide a corps of engineers in

accordance with such requirements. The "field companies" and "fortress

companies" of the R.E. represent the traditional tactical application of

their arm to works of offence and defence in field and siege warfare.

The balloon, telegraph, and other branches, also organized on a

permanent footing, represent the modern application of scientific aids

in warfare. (See FORTIFICATION AND SIEGECRAFT; TACTICS; INFANTRY, &c.)

_History._--It is difficult to distinguish between military and civil

engineers in the earlier ages of modern history, for all engineers acted

as builders of castles and defensible strongholds, as well as

manufacturers and directors of engines of war with which to attack or

defend them. The annals of fortification show professors, artists, &c.,

as well as soldiers and architects, as designers and builders of

innumerable systems of fortification. By the middle of the 13th century

there was in England an organized body of skilled workmen employed under

a "chief engineer." At the siege of Calais in 1347 this corps consisted

of masons, carpenters, smiths, tentmakers, miners, armourers, gunners

and artillerymen. At the siege of Harfleur in 1415 the chief engineer

was designated Master of the King's Works, Guns and Ordnance, and the

corps under him numbered 500 men, including 21 foot-archers.

Headquarters of engineers existed at the Tower of London before 1350,

and a century later developed into the Office of Ordnance (afterwards

the Board of Ordnance), whose duty was to administer all matters

connected with fortifications, artillery and ordnance stores.

Henry VIII. employed many engineers (of whom Sir Richard Lee is the best

known) in constructing coast defences from Penzance to the Thames and

thence to Berwick-on-Tweed, and in strengthening the fortresses of

Calais and Guines in France. He also added to the organization a body of

pioneers under trench-masters and a master trenchmaster. Charles II.

increased the peace establishment of engineers and formed a separate one

for Ireland, with a chief engineer who was also surveyor-general of the

King's Works. In both countries only a small permanent establishment was

maintained, a special ordnance train being enrolled in war-time for each

expedition and disbanded on its termination. The commander of an

ordnance train was frequently, but not necessarily, an engineer, but

there was always a chief engineer of each train. At Blenheim (1704)

Marlborough's ordnance train was commanded by Holcroft Blood, a

distinguished engineer. But after the rebellion of 1715 it was decided

to separate the artillery from the engineers, and the royal warrant of

26th May 1716 established two companies of artillery as a separate

regiment, and an engineer corps composed of 1 chief engineer, 3

directors, 6 engineers-in-ordinary, 6 engineers extraordinary, 6

sub-engineers and 6 practitioner engineers.

Until the 14th of May 1757 officers of engineers frequently held, in

addition to their military rank in the corps of engineers, commissions

in foot regiments; but on and after that date all engineer officers were

gazetted to army as well as engineer rank--the chief engineer as colonel

of foot, directors as lieutenant-colonel, and so forth down to

practitioners as ensigns. On the 18th of November 1782 engineer grades,

except that of chief engineer, were abolished, and the establishment was

fixed at 1 chief engineer and colonel, 6 colonels commandant, 6

lieutenant-colonels, 9 captains, 9 captain lieutenants (afterwards

second captains), 22 first lieutenants, and 22 second lieutenants. Ten

years later a small invalid corps was formed. In 1787 the designation

"Royal" was conferred upon the engineers, and its precedence settled to

be on the right of the army, with the royal artillery.

In 1802 the title of chief engineer was changed to inspector-general of

fortifications. From this time to the conclusion of the Crimean War

various augmentations took place, consequent on the increasing and

widely extending duties thrown upon the officers. These, in addition to

ordinary military duties, comprised the construction and maintenance of

fortifications, barrack and ordnance store buildings, and all

engineering services connected with them. The cadastral survey of the

United Kingdom (called the "Ordnance Survey") had been entrusted to the

engineers as far back as 1784, and absorbed many officers in its

execution.

In 1772 the formation at Gibraltar of "The Company of Soldier

Artificers," officered by Royal Engineers, was authorized, and a second

company was added soon afterwards. In 1787 by royal warrant "The Corps

of Royal Military Artificers" was established at home, consisting of six

companies, with which the Gibraltar companies were amalgamated. In 1806

this corps was doubled, and in 1811 increased to 32 companies. In 1813

its title was changed to "The Royal Sappers and Miners." In 1856, at the

close of the Crimean War, it was incorporated with "The Corps of Royal

Engineers," by whom it had always been officered. At that date the corps

numbered about 340 officers and 4000 non-commissioned officers and men,

in 1 troop and 32 companies.

In 1770 the East India Company reorganized the engineer corps of the

three presidencies, composed of officers only. Native corps of sappers

or pioneers were formed later, and officered principally by engineers.

The officers of engineers were employed in peacetime on the public works

of the country, their services when required being placed at the

disposal of the military authorities. The Indian Engineers have not only

distinguished themselves in the operations of war, but have left

monuments of engineering skill in the irrigation works, railways,

surveys, roads, bridges, public buildings and defences of the country.

When Indian administration was transferred to the crown (1862) the

Indian Engineers became "Royal," so that there now exists but one corps,

the Royal Engineers. This is composed of about 1000 officers and 7700

warrant and non-commissioned officers and men. Of the officers some 220

are attached to units, about 400 employed either at home or in the

colonies on engineering duties in military commands, on the staff, or on

special duty, and about 370 on the Indian establishment. The supreme

technical control of the Royal Engineers is exercised from the War

Office. See also UNITED KINGDOM; ARMY.

The history of the French engineers shows a somewhat similar line of

development. Originally selected officers of infantry were given brevets

as engineers, and these men performed military and also civil duties for

the king's service by the aid of companies of workmen enlisted and

discharged from time to time. Vauban (q.v.) was the founder of the

famous _corps de Genie_ (1690). Its members were selected officers and

civilians, employed in all branches of military and naval services, and

it soon achieved its European reputation as the first school of

fortification and siegecraft. It received a special uniform in 1732.

About 1755 it was for a time merged in the artillery. In 1766 the title

of _Genie_ was conferred upon the officers, and the same name (_troupes

de Genie_) was given to the previously existing companies of sappers and

miners in 1801.

In the United States the separate Corps of Engineers (since 1794 there

had been a Corps of Artillerists and Engineers) was organized in 1802,

starting with a small body stationed at West Point, which in 1838 and

1846 was gradually increased, and in 1861 given three additional

companies. In 1866 they were formed into a battalion and stationed at

Willets Point, N.Y. In 1901 they were reorganized in three battalions,

with a total strength of 1282. The U.S. Engineer School, formerly at

Willets Point, was transferred in 1901 to Washington. Until 1866 the

military academy at West Point was under the supervision of the Corps of

Engineers, but from that time its direction was thrown open; but the

highest branch at West Point is still regarded as that of the engineers.

The Corps of Engineers has done a great deal of highly important work in

the United States, notably in building forts, and improving rivers and

harbours for navigation.

See Maj.-Gen. R.W. Porter, _Hist, of the Corps of Royal Engineers_

(Chatham, 1889); C. Lecomte, _Les Ingenieurs militaires de la France_

(Paris, 1903); H. Frobenius, _Geschichte der K. preuss. Ingenieur- und

Pioneer-Korps_ (Berlin, 1906).

ENGIS, a cave on the banks of the Meuse near Liege, Belgium, where in

1832 Dr P.C. Schmerling found human remains in deposits belonging to the

Quaternary period. Bones of the cave-bear, mammoth, rhinoceros and hyena

were discovered in association with parts of a man's skeleton and a

human skull. This, known as "the Engis Skull," gave rise to much

discussion among anthropologists, since it has characteristics of both

high and low development, the forehead, low and narrow, indicating

slight intelligence, while the abnormally large brain cavity contradicts

this conclusion. Of it Huxley wrote: "There is no mark of degradation

about any part of its structure. It is a fair average human skull, which

might have belonged to a philosopher, or might have contained the

thoughtless brains of a savage." Dr Schmerling concluded that the human

remains were those of man who had been contemporary with the extinct

mammals. As, however, fragments of coarse pottery were found in the cave

which bore other evidence of having been used by neolithic man, by whom

the cave-floor and its contents might have been disturbed and mixed, his

arguments have not been regarded as conclusive. There is, however, no

doubt as to the great age of the Engis Skull. Discoveries of a like

nature were made by Dr Schmerling in the neighbourhood in the caves of

Engihoul, Chokier and others.

See P.C. Schmerling, _Recherches sur les ossements decouverts dans les

cavernes de la province Liege_ (1833); Huxley, _Man's Place in

Nature_, p. 156; Lord Avebury, _Prehistoric Times_, p. 317 (1900).