Electricity sentence example

electricity
  • After a century, electricity was still being generated.
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  • Probably some run down shack without electricity or running water - and how much of the 40 acres was vertical?
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  • When did the electricity come on?
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  • That great separation of positive and negative electricity sometimes takes place during rainfall is undoubted, and the charge brought to the ground seems preponderatingly negative.
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  • The air was filled with electricity and the battlefield a mix of red fog and purple lightening.
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  • Something about the man made her feel safe, and the warm electricity in her body made her sleepy.
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  • There was no electricity in this part of the state, and looters would've likely taken everything.
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  • Yeah, but let's take care of the electricity first.
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  • Their land phone was dependent on electricity.
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  • Twenty-five percent of all of the electricity used in the restaurant is generated by the sun.
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  • The city is well drained and possesses a good water supply; it is lighted by electricity and has an electric car system.
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  • The municipality owns and operates the water-works (the water-supply being drawn from the Penobscot by the Holly system) and an electric-lighting plant; there is also a large electric plant for generation of electricity for power and for commercial lighting, and in Bangor and the vicinity there were in 1908 about 60 m.
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  • The conductivity for heat (Wiedemann and Franz) or electricity is 8.5, that of silver being taken as loo.
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  • Until 1820 all the artificial magnets in practical use derived their virtue, directly or indirectly, from the natural magnets found in the earth: it is now recognized that the source of all magnetism, not excepting that of the magnetic ore itself, is electricity, and it is usual to have direct recourse to electricity for producing magnetization, without the intermediary of the magnetic ore.
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  • We must refer the reader for further information to his monumental work entitled Experimental Researches on Electricity, in three volumes, reprinted from the Phil.
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  • The 3rd series (1833) he devoted to discussion of the identity of electricity derived from various sources, frictional, voltaic, animal and thermal, and he proved by rigorous experiments the identity and similarity in properties of the electricity generated by these various methods.
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  • The voltameter provided a means of measuring quantity of electricity, and in the hands of Faraday and his successors became an appliance of fundamental importance.
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  • The 19th series (1845) contains an account of his brilliant discovery of the rotation of the plane of polarized light by transparent dielectrics placed in a magnetic field, a relation which established for the first time a practical connexion between the phenomena of electricity and light.
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  • Lenz (1804-1865), 1 Amongst the most important of Faraday's quantitative researches must be included the ingenious and convincing proofs he provided that the production of any quantity of electricity of one sign is always accompanied by the production of an equal quantity of electricity of the opposite sign.
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  • See Experimental Researches on Electricity, vol.
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  • So far we have tended to represent the activity of the sacred as that of a universal force, somewhat in the style of our " electricity" or " mind.
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  • But it was not until the dynamo was improved as a machine for generating large quantities of electricity at a very low cost that the electrolysis of copper could be practised on a commercial scale.
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  • His investigations occupied almost the whole field of science, including physiology, physiological optics, physiological acoustics, chemistry, mathematics, electricity and magnetism, meteorology and theoretical mechanics.
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  • In physiological science he investigated quantitatively the phenomena of animal heat, and he was one of the earliest in the field of animal electricity.
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  • For the later years of his life his labours may be summed up under the following heads: (1) On the conservation of energy; (2) on hydro-dynamics; (3) on electro-dynamics and theories of electricity; (4) on meteorological physics; (5) on optics; and (6) on the abstract principles of dynamics.
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  • A transporter bridge between Runcorn and Widnes, with a suspended car worked by electricity to convey passengers and vehicles (the first bridge of the kind in England) was constructed in 1902.
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  • A weight is put in the opposite scale pan and a measured charge of electricity is given to the disk C just sufficient to tip over the balance.
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  • Since the distribution of electricity may be considered to be constant over the surface S of the attracted disk, the mechanical force f on it is given by the expression,' f S(V - v)2 8 ird2 where d is the distance between the two plates.
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  • The movable plate can be drawn down into a definite sighted position when a difference of potential is made between the two ' See Maxwell, Treatise on Electricity and Magnetism (2nd ed.), i.
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  • There are very numerous sawmills, using waterpower, steam and electricity; they are situated chiefly in the coast districts of the Gulf of Bothnia, from Gefle northwards, especially in the neighbourhood of Sundsvall and along the Angerman River, and in the neighbourhood of all the ports as far north as Lulea and Haparanda.
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  • Electricity was subsequently applied to the tramway system.
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  • During this period he was not only most successful as a teacher, but produced much original work - especially in the experimental and mathematical treatment of electricity - which is still regarded as standard.
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  • If these means fail, exercise, massage and electricity may help a cure.
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  • The employment of electricity, in long continued and intractable forms of neuralgia, proves in many instances eminently serviceable.
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  • He has also found that this action is reversible, for when the area of the surface of contact of the acid and mercury is made to increase, an electric current passes from the mercury to the acid, the amount of electricity which passes while the surface increases by one square centimetre being sufficient to decompose.
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  • Electricity, as has long been known, has an extraordinary influence upon the appearance of a fine jet of water ascending in a nearly perpendicular direction.
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  • The second effect is readily attributed to the mutual repulsion of the electrified drops, but the action of feeble electricity in producing apparent coherence was long unexplained.
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  • If the water be soapy, and especially if it contain a small proportion of milk, coalescence ensues without the help of electricity.
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  • The town is lighted with gas supplied by a gas company first incorporated in 1830 and by electricity supplied by the corporation.
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  • In 1904 electricity, generated by water-power from the rivers, notably the Snake, began to be utilized in mining operations.
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  • In 1881 appeared his Elementary Lessons in Electricity and Magnetism, twice reprinted in 1882 and 16 times in the ensuing 12 years.
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  • Gilbert's is therefore not merely the first, but the most important, systematic contribution to the sciences of electricity and magnetism.
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  • In 1834 he continued and extended his researches "On the Influence of a Spiral Conductor in increasing the Intensity of Electricity from a Galvanic Arrangement of a Single Pair," a memoir of which was read before the American Philosophical Society on the 5th of February 1835.
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  • The five numbers of his Contributions to Electricity and Magnetism (1835-1842) were separately republished from the Transactions.
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  • Its thermal conductivity is, according to Wiedemann and Franz, superior to that of other metals, being in the ratio of ioo: 74 as compared with copper and loo: J4 with gold; it is the most perfect conductor of electricity, standing to copper in the ratio ioo: 75, and to gold I oo: 73.
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  • At Genoa he investigated the electricity of the torpedo-fish, and at Florence, by the aid of the great burning-glass in the Accademia del Cimento, he effected the combustion of the diamond in oxygen and decided that, beyond containing a little hydrogen, it consisted of pure carbon.
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  • In the spring of 1828 he again left England for Illyria, and in the winter fixed his residence at Rome, whence he sent to the Royal Society his "Remarks on the Electricity of the Torpedo," written at Trieste in October.
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  • Electricity, generated at the Shenandoah river, is used for power in many of the factories.
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  • Another discussed conduction in curved sheets; a third the distribution of electricity in two influencing spheres; a fourth the deter mination of the constant on which depends the intensity of induced currents; while others were devoted to Ohm's law, the motion of electricity in submarine cables, induced magnetism, &c. In other papers, again, various miscellaneous topics were treated - the thermal conductivity of iron, crystalline reflection and refraction, certain propositions in the thermodynamics of solution and vaporization, &c. An important part of his work was contained in his Vorlesungen fiber mathematische Physik (1876), in which the principles of dynamics, as well as various special problems, were treated in a somewhat novel and original manner.
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  • Under the Electric Lighting Acts the Board of Trade may license any district council to supply electricity, or may grant to them a provisional order for the same purpose.
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  • It is now almost the exception, at least in urban districts, to find a district council which has not obtained a provisional order under these acts, and for the most part the undertakings of local authorities in the way of supplying electricity have been very prosperous.
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  • The department of public safety controls the bureaus of police, detectives, fire, health, electricity and building inspection; the department of public works controls bureaus of surveys, construction, highways and sewers, city property, water, assessment of water rents, parks, deed registry, bridges and light.
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  • In the future, we will paint surfaces with substances full of nanites that will absorb sunlight and turn it into electricity, transforming any object we paint into a clean energy creator.
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  • When you two walked in, I could feel the electricity.
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  • Grandpa, my mother's father,  originally built this place in the nineteen-thirties and wired it for electricity years later.
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  • She'd shorted out the electricity.
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  • Lights from lasers and muzzle fire spotted the forest below them before they reached an urban area, mostly dark with several patches of electricity.
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  • They're the only ones with electricity.
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  • At least we didn't lose electricity.
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  • Their kiss was like an Arkansas storm - wild, warm and full of electricity.
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  • If V be the potential, p the density of free electricity at a point in the atmosphere, at a distance r from the earth's centre, then assuming statical conditions and neglecting variation of V in horizontal directions, we have r2 (d/dr) (r 2 dV/dr) - - 4.rp = o.
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  • Starting from an observation of Marconi's, a number of interesting facts have been accumulated on the absorbing effect of sunlight on the propagation of long Hertzian waves through space, and on the disturbing effects of atmospheric electricity as well as upon the influence of earth curvature and obstacles of various kinds interposed in the line between the sending and transmitting stations.4 Electric wave telegraphy has revolutionized our means of communication from place to place on the surface of the earth, making it possible to communicate instantly and certainly between places separated by several thousand miles, whilst The Electrician, 1904, 5 2, p. 407, or German Pat.
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  • The term " telephony " was first used by Philipp Reis of Friedrichsdorf, in a lecture delivered before the Physical Society of Frankfort in 1861.1 But, although this lecture and Reis's subsequent work received considerable notice, little progress was made until the subject was taken up between 1874 and 1876 by Alexander Graham Bell, a native of Edinburgh, then resident in Boston, Mass., U.S.A. Bell, like Reis, employed electricity for the reproduction of sounds; but he attacked the problem in a totally different manner.
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  • Considering the time at which he wrote, Reis seems to have understood very well the nature of the vibrations he had to reproduce, but he failed to comprehend how they could be reproduced by electricity.
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  • The introduction of inductance coils into such circuits renders them more susceptible to trouble from atmospheric electricity and more sensitive to leakage variations.
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  • Italy has only unimportant lignite and anthracite mines, but water power is abundant and has been largely applied to industry, especially in generating electricity.
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  • The richest, however, of the co-operative societies, though few in number, are those for the production of electricity, for textile industries and for ceramic and glass manufactures.
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  • During the working much electricity is developed.
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  • Among the schools may be mentioned the magnificently equipped Rhenish-Westphalian Polytechnic School (built 1865-1870) and the school of mining and electricity, founded in 1897.
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  • The density of solid sulphur is 2 062 to 2'070, and the specific heat 0.1712; it is a bad conductor of electricity and becomes negatively electrified on friction.
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  • The city is lighted by gas and electricity, - it was one of the first cities in the United States to adopt electric lighting, - and has a good watersupply system, owned by a private corporation, with a 41 acre filter plant of 18,000,000 gallons per diem capacity and an additional supply of water pumped from deep wells outside the city.
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  • The streets are lighted with electricity; and there are electric street railways and telephones in the city.
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  • In this case electricity was to be the motive-power, and speeds exceeding ioo m.
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  • As to lighting, the oil lamp has been largely displaced by gas and electricity.
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  • In the operation of intra-urban railwa y s, steam locomotives, cables and electricity have severally been tried: the first having been used in the earlier examples of underground lines and in the various elevated systems in the United States.
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  • The cable is slow; and unless development along new lines of com p ressed air or some sort of chemical engine takes place, electricity will monopolize the field.
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  • Electricity is applied through a separate locomotive attached to the head of the train, or through motor carriages attached either at one end or at both ends of the train, or by putting a motor on every axle and so utilizing the whole weight of the train for traction, all the motors being under a single control at the head of the train, or at any point of the train for emergency.
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  • With electricity, power can be applied to as many axles in the train as desired, and so the whole weight of the train, with its load, may be utilized if necessary.
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  • But the great work of his life was devoted to electricity.
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  • Gauss had shown how to reduce all the phenomena of statical electricity to mere attractions and repulsions exerted at a distance by particles of an imponderable on one another.
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  • The step to magnetic phenomena was comparatively simple; but it was otherwise as regards electromagnetic phenomena, where current electricity is essentially involved.
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  • Three years later he removed to Warrington as classical tutor in a new academy, and there he attended lectures on chemistry by Dr Matthew Turner of Liverpool and pursued those studies in electricity which gained him the fellowship of the Royal Society in 1766 and supplied him with material for his History of Electricity.
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  • He also published (1767) a treatise on the History and Present State of Electricity, which embodies some original work, and (1772) a History of Discoveries relating to Vision, Light and Colours, which is a mere compilation.
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  • By far the greater and more important part of his work related to electricity and magnetism.
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  • Combination was associated with the coalescence of these charges, and the nature of the resulting compound showed the nature of the residual electricity.
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  • Another branch, related to energetics, is concerned with the transformation of chemical energy into other forms of energy - heat, light, electricity.
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  • His earliest work was mineralogical in character, but he soon turned his attention to the study of electricity and especially of electrochemistry.
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  • Throughout the central part of Alexandria the streets are paved with blocks of lava and lighted by electricity.
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  • The year 1827 marks the revival of Morse's interest in electricity.
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  • The conversion of nitrogen into ammonia by electricity has received much attention, but the commercial aspect appears to have been first worked out by de Hemptinne in 1900, who used both the spark and silent discharge on mixtures of hydrogen and nitrogen, and found that the pressure and temperature must be kept low and the spark gap narrow.
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  • Berzelius stated that neutral salt solutions could be decomposed by electricity, the acid appearing at one pole and the metal at the other.
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  • When an electric current flows round a circuit, there is no accumulation of electricity anywhere in the circuit, hence the current strength is everywhere the same, and we may picture the current as analogous to the flow of an incompressible fluid.
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  • Acting on this view, Faraday set himself to examine the relation between the flow of electricity round the circuit and the amount of chemical decomposition.
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  • Regarding the current as the passage of a certain amount of electricity per second, it will be seen that the results FIG.
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  • We may sum up the chief results of Faraday's work in the statements known as Faraday's laws: The mass of substance liberated from an electrolyte by the passage of a current is proportional (I) to the total quantity of electricity which passes through the electrolyte, and (2) to the chemical equivalent weight of the substance liberated.
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  • On the view of the process of conduction described above, the amount of electricity conveyed per second is measured by the product of the number of ions, known from the concentration of the solution, the charge carried by each of them, and the velocity with which, on the average, they move through the liquid.
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  • When the zinc and copper plates are connected through a wire, a current flows, the conventionally positive electricity passing from copper to zinc in the wire and from zinc to copper in the cell.
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  • Our views of the nature of the ions of electrolytes have been extended by the application of the ideas of the relations between matter and electricity obtained by the study of electric conduction through gases.
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  • Caoutchouc is a bad conductor of heat and electricity, and alone or mixed with other materials is employed as an electrical insulator.
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  • This solution, being an inferior conductor of electricity, requires a much higher electromotive force to drive the current through it, and is therefore more costly in use.
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  • The micas are bad conductors of heat and electricity, and it is on these properties that many of their technical applications depend.
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  • Thence he was led to his famous researches on the phenomena produced by the discharge of electricity through highly exhausted tubes (sometimes known as "Crookes' tubes" in consequence), and to the development of his theory of "radiant matter" or matter in a "fourth state," which led up to the modern electronic theory.
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  • His morality is not yet separated from his religion; and religion for him means the cult of some superior being - the king or priest of his tribe - whose person is charged with a kind of sacred electricity.
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  • The magnetic field due to a long straight wire in which a current of electricity is flowing is at every point at right angles to the plane passing through it and through the wire; its strength at any point distant r centimetres from the wire is H = 21/r, (2) i being the current in C.G.S.
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  • The factor of proportionality will be I-41r, so that ' The principal theoretical investigations are summarized in Mascart and Joubert's Electricity and Magnetism, i.
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  • The total magnetic induction or flux corresponds to the current of electricity (practically measured in amperes); the induction or flux density B to the density of the current (number of amperes to the square centimetre of section); the magnetic permeability to the specific electric conductivity; and the line integral of the magnetic force, sometimes called the magnetomotive force, to the electro-motive force in the circuit.
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  • Nevertheless, many important problems relating to the distribution of magnetic induction may be solved by methods similar to those employed for the solution of analogous problems in electricity.
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  • Thomson, Electricity and Magnetism, § 205.
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  • If the conductor consists of a coil of wire the ends of which are connected with a suitable galvanometer, the integral electromotive force due to a sudden increase or decrease of the induction through the coil displaces in the circuit a quantity of electricity Q=SBns R, where SB is the increment or decrement of induction per square centimetre, s is the area of the coil, n the number of turns of wire, and R the resistance of the circuit.
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  • There C are no important industries, except a few flour-mills, some glass works, iron foundries, a motor car factory, straw hat factories, and power-houses supplying electricity for lighting and for the numerous tramcars.
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  • It also works coal-fields at Yentai and Fushun; has a line of steamers plying between Tairen and Shanghai; and engages in enterprises of electricity, warehousing and the management of houses and lands within zones 50 Ii (17 m.) wide on either side of the line.
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  • On passing a current of electricity, of which the volume and pressure are adjusted to the conditions of the electrolyte and electrodes, the anode slowly dissolves, leaving the insoluble impurities in the form of a sponge, if the proportion be considerable, but otherwise as a mud or slime which becomes detached from the anode surface and must be prevented from coming into contact with the cathode.
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  • He entered holy orders and ultimately attained the rank of abbe; but his tastes all lay in the direction of experimental research, especially on the subject of electricity.
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  • Besides their ordinary condition all bodies are capable of being thrown into a physical state in which they are said to be electrified or charged with electricity.
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  • When in this condition they become sources of electric force, and the space round them in which this force is manifested is called an " electric field " (see Electricity).
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  • This shows that some bodies are conductors and others non-conductors or insulators of electricity, and that bodies can be electrified by friction and impart their electric charge to other bodies.
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  • This proves the existence of two kinds of electricity, called positive and negative.
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  • The sealing-wax so treated is electrified negatively or resinously, and the glass with positive or vitreous electricity.
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  • The electrified ebonite is said to act by " electrostatic induction " on the tray, and creates on it two induced charges, one of positive and the other of negative electricity.
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  • The leaves of the electroscope will diverge with positive electricity.
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  • This experiment proves that when a charged body acts by induction on an insulated conductor it causes an electrical separation to take place; electricity of opposite sign is drawn to the side nearest the inducing body, and that of like sign is repelled to the remote side, and these quantities are equal in amount.
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  • If a small conducting body is charged with Q electrostatic units of electricity, and placed in any electric field at a point where the electric force has a value E, it will be subject to a mechanical force equal to QE dynes, tending to move it in the direction of the resultant electric force.
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  • The reader should, however, notice that what is generally called electric force is the analogue in electricity of the so-called acceleration of gravity in mechanics, whilst electrification or quantity_of electricity is analogous to mass.
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  • If we consider a very small conductor charged with a unit of positive electricity to be placed in an electric field, it will move or tend to move under the action of the electric force in a certain direction.
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  • We may define the term potential difference otherwise by saying that it is the work done in carrying a small conductor charged with one unit of electricity from one point to the other in a direction opposite to that in which it would move under the electric forces if left to itself.
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  • Suppose then that we have a conductor charged with electricity,we may imagine its surface to be divided up into small unequal areas, each of which carries a unit charge of electricity.
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  • These surfaces are called "equipotential" or "level surfaces," and we may so locate them that the potential difference between two adjacent surfaces is one unit of potential; that is, it requires one absolute unit of work (I erg) to move a small body charged with one unit of electricity from one surface to the next.
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  • The surface of a charged conductor is an equipotential surface, because when the electric charge is in equilibrium there is no tendency for electricity to move from one part to the other.
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  • Potential in a certain sense is to electricity as difference of level is to liquids or difference of temperature to heat.
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  • Electricity tends to flow from places of high to places of low potential, water to flow down hill, and heat to move from places of high to places of low temperature.
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  • For since electricity tends to move between points or conductors at different potentials, if the electricity is at rest on them the potential must be everywhere the same.
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  • It can be shown that the resultant electric force normal to the surface at a point just outside a conductor is 1 See Maxwell, Elementary Treatise on Electricity (Oxford, 1881), P. 47.
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  • The fact that there is no electric force in the interior of such a closed electrified shell is one of the most certainly ascertained facts in the science of electrostatics, and it enables us to demonstrate at once that particles of electricity attract and repel each other with a force which is inversely as the square of their distance.
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  • The electric density on the sphere being uniform, the quantities of electricity on these areas are proportional to the areas, and if the electric force varies inversely as the square of the distance, the forces exerted by these two surface charges at the point in question are proportional to the solid angle of the little cone.
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  • It is not even necessary that 2 See Maxwell, Treatise on Electricity and Magnetism (3rd ed., Oxford, 1892), vol.
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  • The potential of a conductor has already been defined as the mechanical work which must be done to bring up a very small body charged with a unit of positive electricity from the earth's surface or other boundary taken as the place of zero potential to the surface of this conductor in question.
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  • Thus, consider a sphere uniformly charged with Q units of positive electricity.
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  • The quantity of electricity which must be given to the sphere to raise it to unit potential is therefore R electrostatic units.
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  • Since the potential of a small charge of electricity dQ at a distance r is equal to dQ/r, and since the potential of all parts of a conductor is the same in those cases in which the distribution of surface density of electrification is uniform or symmetrical with respect to some point or axis in the conductor, we can calculate the potential by simply summing up terms like rdS/r, where dS is an element of surface, o- the surface density of electricity on it, and r the distance from the symmetrical centre.
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  • Thus the distribution of electricity on a sphere in free space must be uniform, and all parts of the charge are at an equal distance R from the centre.
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  • We have first to determine the mode in which electricity distributes itself on a conducting ellipsoid in free space.
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  • Thus if Q is the surface density, S the thickness of the shell at any point, and p the assumed volume density of the matter of the shell, we have v =Abp. Then the quantity of electricity on any element of surface dS is A times the mass of the corresponding element of the shell; and if Q is the whole quantity of electricity on the ellipsoid, Q =A times the whole mass of the shell.
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  • Accordingly for a given ellipsoid the surface density of free distribution of electricity on it is everywhere proportional to the the tangent e plane e att that point.
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  • Accordingly the distribution of electricity is such that equal parallel slices of the ellipsoid of revolution taken normal to the axis of revolution carry equal charges on their curved surface.
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  • The reader is also referred to an article by Lord Kelvin (Reprint of Papers on Electrostatics and Magnetism, p. 178), entitled " Determination of the Distribution of Electricity on a Circular Segment of a Plane, or Spherical Conducting Surface under any given Influence," where another equivalent expression is given for the capacity of an ellipsoid.
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  • The final outcome of these investigations was the hypothesis that Thomson's corpuscles or particles composing the cathode discharge in a high vacuum tube must be looked upon as the ultimate constituent of what we call negative electricity; in other words, they are atoms of negative electricity, possessing, however, inertia, and these negative electrons are components at any rate of the chemical atom.
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  • Each electron is a point-charge of negative electricity equal to 3.9 X Io 1 ° of an electrostatic unit or to.
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  • Thomson also developed this hypothesis in a profoundly interesting manner, and we may therefore summarize very briefly the views held on the nature of electricity and matter at the beginning of the 10th century by saying that the term electricity had come to be regarded, in part at least, as a collective name for electrons, which in turn must be considered as constituents of the chemical atom, furthermore as centres of certain lines of self-locked and permanent strain existing in the universal aether or electromagnetic medium.
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  • Larmor and many others, the electronic hypothesis of matter and of electricity has been developed in great detail and may be said to represent the outcome of modern researches upon electrical phenomena.
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  • In England the broad distinction between " presses " and " machines " is generally considered to rest in the fact that the former are worked by hand, and the latter by steam, gas or electricity; and the men who work by these two methods are called respectively " pressmen " and " machine minders " or " machine managers."
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  • Electricity is supplanting both steam and gas, and is being installed in most large printing-houses, including newspaper offices.
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  • Suction gas is being tried in some offices as a supplanter of electricity and is said to be much cheaper as a power producer.
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  • To-day, by reason of other uses to which electricity is applied, electrically deposited copper of high conductivity is in everincreasing demand, and commands a higher price than copper refined by fusion.
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  • Details of his experimental work in magnetism and the problems of electricity and light are given in 17.3 8 9, 39 1 and 346, 6.859, 9.206, 21.936.
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  • He published numerous works on different branches of physics, including A Complete Treatise on Electricity (1777), Treatise on the Nature and Properties of Air and other permanently Elastic Fluids (1781), History and Practice of Aerostation (1785), Treatise on Magnetism (1787), Elements of Natural and Experimental Philosophy (1803), Theory and Practice of Medical Electricity (1780), and Medical Properties of Factitious Air (1798).
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  • The city is mainly lighted by electricity, which has also found its way into all the public edifices and most private houses.
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  • The conductivity gives us the amount of electricity conveyed per second under a definite electromotive force.
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  • Hence if we distribute electricity.
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  • Since then they are all charged with the same quantity of electricity, and the total over all potential difference V is the sum of each of the individual potential differences V1, V2, V3, &c., we have Q=C I V I =C 2 V 2 =C 3 V 3 =&c., and V=V1-FV2+V3+&c. The resultant capacity is C = Q/V, and C= I/(I/C1 +I /C2+1/C3+&c) = I/Z(I /C) (15).
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  • We now proceed to consider in more detail the laws which govern the distribution of electricity at rest upon conductors.
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  • We have then a very important theorem as follows: - If any closed surface be described in an electric field which wholly encloses or wholly excludes electrified bodies, then the total flux through this surface is equal to 47r - times the total quantity of electricity within it.'
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  • Hence the total electric flux due to a charge Q through an enclosing surface is 41rQ, and therefore is zero through one enclosing no electricity.
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  • If, however, we defined the strength of the source by the statement that the strength divided 1 The beginner is often puzzled by the constant appearance of the factor 47r in electrical theorems. It arises from the manner in which the unit quantity of electricity is defined.
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  • Let this rectangular prism be supposed to be wholly filled up with electricity of density p; then the total quantity in it is p dx dy dz.
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  • Hence if dS and dS' are the areas of the ends, and +E and - E' the oppositely directed electric forces at the ends of the tube, the surface integral of normal force on the flux over the tube is EdS - E'dS' (20), and this by the theorem already given is equal to zero, since the tube includes no electricity.
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  • The above is a statement of Coulomb's law, that the electric fores at the surface of a conductor is proportional to the surface density of the charge at that point and equal to 41r times the density.3 See Maxwell, Electricity and Magnetism, vol.
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  • Every tube of electric force must therefore begin and end on electrified surfaces of opposite sign, and the quantities of positive and negative electricity on its two ends are equal, since the force E just outside an electrified surface is normal to it and equal to a/41r, where a is the surface density; and since we have just proved that for the ends of a tube of force EdS = E 1 dS', it follows that adS = a'dS', or Q = Q', where Q and Q' are the quantities of electricity on the ends of the tube of force.
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  • Since the potential of a conductor is defined to be the work required to move a unit of positive electricity from the surface of the earth or from an infinite distance from all electricity to the surface of the conductor, it follows that the work done in putting a small charge dq into a conductor at a potential v is v dq.
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  • Let us then suppose that a conductor originally at zero potential has its potential raised by administering to it small successive doses of electricity dq.
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  • Hence that distribution of potential which is neces 1 See Maxwell, Electricity and Magnetism, vol.
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  • The same reasoning can be applied to determine the electrical image of a point-charge of positive electricity in a spherical surface, and therefore the distribution of induced electricity over a metal sphere connected to earth produced by a point-charge near it.
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  • If we make a distribution of negative electricity over it, which has a density a varying according to the law a = -(d 2 -r 2) q /42rr AP3.
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  • The student will find it to be a great advantage to read through Faraday's three volumes entitled Experimental Researches on Electricity, as soon as he has mastered some modern elementary book giving in compact form a general account of electrical phenomena.
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  • Everett, Electricity, founded on part iii.
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  • The general illuminant is electricity, and both electrical and gas services are owned by the municipality.
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  • Gold is dissipated by sending a powerful charge of electricity through it when in the form of leaf or thin wire.
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  • Two companies provide Bangkok with a complete system of electric tramways, and the streets are lined with shade-trees and lit by electricity.
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  • The pumps, placed close to the point where the water accumulates, may be worked by an engine on the surface by means of heavy reciprocating rods which pass down the shaft, or by underground motors driven by steam, compressed air or electricity.
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  • In mines that are worked from the outcrop by adits or day levels traction by locomotives driven by steam, compressed air or electricity is used to some extent.
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  • The power so developed is generally utilized in the production of electricity, for which there is an abundant use about large collieries.
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  • Many attempts have been made to produce the substance without electricity, but have met with no commercial success.
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  • When a liquid undergoing evaporation is contained in a closed vessel, a molecule which has left the liquid will, after a certain 1 Other processes also help in the conduction of heat, especially in substances which are conductors of electricity.
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  • The study of electricity he took up in 1746 when he first saw a Leyden jar, in the manipulation of which he became expert and which he improved by the use of granulated lead in the place of water for the interior armatures; he recognized that condensation is due to the dielectric and not to the metal coatings.
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  • He overthrew entirely the " friction " theory of electricity and conceived the idea of plus and minus charges (1753); he thought the sea the source of electricity.
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  • Experiments and Observations on Electricity (London, 1769) was translated into French by Barbeu Dubourg (Paris, 1773); Vaughan attempted a more complete edition, Political, Miscellaneous and Philosophical Pieces (London, 1 779); an edition in three volumes appeared after Franklin's death (London, 1806); what seemed the authentic Works, as it was under the care of Temple Franklin, was published at London (6 vols., 1817-1819; 3 vols., 1818) and with some additional matter at Philadelphia (6 vols., 1818).
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  • Execution by electricity has been the death penalty since 1898.
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  • This subject he was led to study by the experience of a colliery engineman, who noticed that he received a sharp shock on exposing one hand to a jet of steam issuing from a boiler with which his other hand was in contact, and the inquiry was followed by the invention of the "hydro-electric" machine, a powerful generator of electricity, which was thought worthy of careful investigation by Faraday.
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  • Outside the Indian districts of the eastern and southern outskirts, the streets are paved with asphalt and stone, lighted with electricity and gas, and served with an efficient street railway service.
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  • Ozone occurs, in an amount supposed to be associated with the development of atmospheric electricity (lightning, &c.); this amount varies with the seasons, being a maximum in spring, and decreasing through summer and autumn to a minimum in winter.
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  • Besides the breadth of its scope, in which the American census stands unrivalled, the most important American contribution to census work has been the application of electricity to the tabulation of the results, as was first done in 1890.
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  • Recently the practice of driving rolls by electricity has been growing, the advantage being that each pair of rolls can be driven independently without the intervention of cumbrous shafting.
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  • Heavy blanks have also been reduced chemically by making them part of the anode in a cyanide bath through which a current of electricity is passed.
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  • The falls of the Hudson here furnish a fine water-power, which is utilized, in connexion with steam and electricity, in the manufacture of lumber, paper and wood pulp, women's clothing, shirts, collars and cuffs, &c. In 1905 the village's factory products were valued at $4,780,331.
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  • It is an attractive town in a pleasant situation, with fine broad streets lined with shady trees, and was the first town in Australia to be lighted by electricity.
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  • Electricity is obtained by two gas engines (one spare) each of 75 B.H.P.
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  • Although he received some instruction from John Dalkon in chemistry, most of his scientific knowledge was selftaught, and this was especially the case with regard to electricity and electro-magnetism, the subjects in which his earliest researches were carried out.
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  • At the age of nineteen he invented an electromagnetic engine, and in the course of examining its performance dissatisfaction with vague and arbitrary methods of specifying elec rical quantities caused him to adopt a convenient and scie tific unit, which he took to be the amount of electricity req ired to decompose nine grains of water in one hour.
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  • In 1840 he ', as thus enabled to give a quantitative statement of the law acc s rding to which heat is produced in a conductor by the pas ageof an electric current, and in succeeding years he publish d a series of valuable researches on the agency of electricity in ansformations of energy.
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  • A great economic and social programme 'was announced, including the extension of waterways, the exploitation of electricity, an improved system of communication, industrial insurance, and a department for public health.
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  • Gounelle measured the velocity of electricity.
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  • The next years were much occupied with scientific work, especially the study of heat, light and electricity, on which he presented memoirs to the Academie des Sciences, but the academicians were horrified at his temerity in differing from Newton, and, though acknowledging his industry, would not receive him among them.
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  • The shunted voltameter was then inserted in series with the electric supply mains leading to the house or building taking electric energy, and the current which passed dissolved the zinc from one plate and deposited it upon the other, so that after a certain interval of time had elapsed the altered weight of the plates enabled the quantity of electricity to be determined from the known fact that an electric current of one ampere, flowing for one hour, removes 1.2533 grammes of zinc from a solution of sulphate of zinc. Hence the quantity in amperehours passing through the electrolytic cell being known and the fraction of the whole quantity taken by the cell being known, the quantity supplied to the house was determined.
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  • The quantity of electricity which is passed is estimated by the diminution in the volume of the liquid.
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  • It follows that the number of the revolutions the mercury makes in a given time is proportional to the quantity of electricity which is passed through the meter.
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  • An electricity meter should therefore have approximately the same accuracy.
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  • In the Long-Schattner electrolytic meter, the insertion of the coin depresses a copper plate or plates into an electrolytic cell containing a solution of sulphate of copper; the passage of the current dissolves the copper off one of the plates, the loss in weight being determined by the quantity of the electricity passed.
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  • The streets are narrow, irregular and roughly paved, but are lighted by electricity; tramway lines run between the principal points of the city and suburbs.
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  • It has to be competent to transmit the transverse waves of light and electricity, and the other known radiant and electric actions; the way in which this is done is now in the main known, though there are still questions as to the mode of expression and formulation of our knowledge, and also as regards points of detail.
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  • With Dr Hugo Miller as his collaborator he published several papers of a chemical character between the years 1856 and 1862, and investigated, 1868-1883, the discharge of electricity through gases by means of a battery of 14,600 chloride of silver cells.
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  • With all the important work he accomplished in physics - the enunciation of Boyle's law, the discovery of the part taken by air in the propagation of sound, and investigations on the expansive force of freezing water, on specific gravities and refractive powers, on crystals, on electricity, on colour, on hydrostatics, &c. - chemistry was his peculiar and favourite study.
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  • Matthiessen, sodium ranks fourth to silver, copper and gold as a conductor of electricity and heat, and according to Bunsen it is the most electropositive metal with the exception of caesium, rubidium and potassium.
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  • Graphite is black and opaque, whilst diamond is colourless and transparent; it is one of the softest (H= I) of minerals, and diamond the hardest of all; it is a good conductor of electricity, whilst diamond is a bad conductor.
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  • It is a very dense form of carbon, and is a good conductor of heat and electricity.
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  • Authoritative standards and instruments for the measurement of electricity, based on the fundamental units of the metric system, have been placed in the Electrical Laboratory of the Board of Trade.
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  • The dynamical series of stages in nature, the forms in which the ideal structure of nature is realized, are matter, as the equilibrium of the fundamental expansive and contractive forces; light, with its subordinate processes - magnetism, electricity, and chemical action; organism, with its component phases of reproduction, irritability and sensibility.'
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  • The city has a large jobbing trade, a coal supply from rich deposits in Pierce county, and abundant water-power from swift mountain streams, which is used for generating electricity for municipal and industrial use.
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  • Practically all the cities' and large towns have electric tramways, and electricity is also used as a motive power on many lines uniting the larger cities with the surrounding towns and villages.
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  • The application of electricity to purposes of manufacture and transportation made the waterfalls and rapids in which the country abounds the source of an almost unlimited supply of energy capable of easy distribution for industrial purposes over wide areas.
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  • They naturally divide themselves into researches on sound, light and electricity, but extend into other branches of physics as well.
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  • The city is lighted by gas and electricity, has an abundant water-supply, and cable connexion with Europe, the United States, other Antilles and South America.
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  • The application of electricity is widely developed on account of the proximity of Alpine valleys rich in torrents.
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  • The streets are lighted with electricity and gas, the Ouvidor and some other narrow streets having a great number of gas-pipe arches across them for decorative illumination on festal occasions.
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  • The city is lighted by electricity generated by the water power of Niagara Falls, and by manufactured gas.
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  • It is a most perfect non-conductor of electricity, and in its dry state the fibres frequently get so electrically excited as to seriously interfere with their working, so that it becomes necessary to moisten them with glycerin or soapy solutions.
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  • Technology, electricity, mining, railways, navigation and many other subjects are now dealt with in international congresses.
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  • At present the quantity of electricity it carries, and also its mass, may be determined, and we can therefore derive units of length and of mass from our electrical measurements.
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  • Passing from Moleschott to Lyell's view of the evolution of the earth's crust and later to Darwin's theory of natural selection and environment, he reached the general inference that, not God but evolution of matter, is the cause of the order of the world; that life is a combination of matter which in favourable circumstances is spontaneously generated; that there is no vital principle, because all forces, non-vital and vital, are movements; that movement and evolution proceed from life to consciousness; that it is foolish for man to believe that the earth was made for him, in the face of the difficulties he encounters in inhabiting it; that there is no God, no final cause, no immortality, no freedom, no substance of the soul; and that mind, like light or heat, electricity or magnetism, or any other physical fact, is a movement of matter.
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  • Withdraw this foundation of bodies as inter-resisting forces causing one another in collision to form a joint mass with a common velocity but without penetration, and the evidence of the third law disappears; for in the case of attractive forces we know nothing of their modus operandi except by the analogy of the collision of inter-resisting bodies, which makes us believe that something similar, we know not what, takes place in gravity, magnetism, electricity, &c. Now, Mach, though he occasionally drops hints that the discovery of the law of collision comes first, yet never explains the process of development from it to the third law of motion.
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  • Half the difference between the two readings gives 1 Annals of Electricity, 18 39, 3, p. 288.
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  • During his first period of discovery, besides the induction of electric currents, Faraday established the identity of the electrification produced in different ways; the law of the definite electrolytic action of the current; and the fact, upon which he laid great stress, that every unit of positive electrification is related in a definite manner to a unit of negative electrification, so that it is impossible to produce what Faraday called "an absolute charge of electricity" of one kind not related to an equal charge of the opposite kind.
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  • After three days he worked with common electricity, trying glass, heavy optical glass, quartz, Iceland spar, all without effect, as on former trials.
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  • He developed a great research laboratory of experimental physics, attracting numerous workers from many countries and colonies; advances were made in the investigation of the conduction of electricity through gases, in the determination of the charge and mass of the electron and in the development of analysis by means of positive rays.
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  • Certain solvents, such as water, liquid ammonia or liquid hydrocyanic acid, possess the power of making some solutes, such as mineral salts and acids, when dissolved in them, conductors of electricity.
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  • Duchenne (Mecanisme de la physiognomie humaine, Paris, 1862) showed that by the use of electricity the action of the separate muscles could be studied and by the aid of photography accurately represented.
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  • In 1808 Sir Humphry Davy, fresh from the electrolytic isolation of potassium and sodium, attempted to decompose alumina by heating it with potash in a platinum crucible and submitting the mixture to a current of electricity; in 1809, with a more powerful battery, he raised iron wire to a red heat in contact with alumina, and obtained distinct evidence of the production of an iron-aluminium alloy.
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  • Before the application of electricity, only two compounds were found suitable for reduction to the metallic state.
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  • The first successful idea of using electricity depended on the enormous heating powers of the arc. The infusibility of alumina was no longer prohibitive, for the molten oxide is easily reduced by carbon.
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  • The motive power for much of the house industry is supplied by electricity.
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  • The electricity is partly furnished by hydraulic works at Paderno, 24 m.
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  • He published many physical memoirs on electricity, the dilatation of liquids by heat, specific heats, capillary attraction, atomic volumes &c. as well as a treatise in 4 volumes on Fisica di corpi ponderabili (1837-1841).
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  • The gas, electricity (1894) and waterworks (1870) are under municipal control.
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  • The glass is excited positively by friction with the rubbers, and the charge is drawn off by the action of the points which, when acted upon inductively, discharge negative electricity against it.
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  • The cushions must be connected to earth to remove the negative electricity which accumulates on them.
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  • Nairne's machine could give either positive or negative electricity, the first named being collected from the prime conductor carrying the collecting points and the second from the prime conductor carrying the cushion.
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  • Likewise the negative charge on B induces a positive charge on the side of B' nearest to it and repels negative electricity to the far side.
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  • The rotation, by destroying the contacts, preserves this unequal distribution, and carries B from A to C at the same time that the tail K connects the ball with the plate C. In this situation, the electricity in B acts upon that in C, and produces the contrary state, by virtue of the communication between C and the ball; which last must therefore acquire an electricity of the same kind with that of the revolving plate.
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  • Here, if we attend to the effect of the whole revolution, we shall find that the electric states of the respective masses have been greatly increased; for the ninety-nine parts in A and B remain, and the one part of electricity in C has been increased so as nearly to compensate ninety-nine parts of the opposite electricity in the revolving plate B, while the communication produced an opposite mutation in the electricity of the ball.
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  • To start the machine the balls were brought in contact, one of the paper armatures electrified, say, with positive electricity, and the disk set in motion.
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  • The action of the machine is as follows: Suppose one paper armature to be charged positively, it acts by induction on the right hand comb, causing negative electricity to issue from the comb points upon the glass revolving disk; at the same time the positive electricity passes through the closed discharge circuit to the left comb and issues from its teeth upon the part of the glass disk at the opposite end of the diameter.
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  • It was an electrostatic and electromagnetic machine combined, driven by an electric current and producing in turn electrostatic charges of electricity.
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  • For one kind of meat we could substitute another; wool could be replaced by cotton, silk or fur; were our common silicate glass gone, we could probably perfect and cheapen some other of the transparent solids; but even if the earth could be made to yield any substitute for the forty or fifty million tons of iron which we use each year for rails, wire, machinery, and structural purposes of many kinds, we could not replace either the steel of our cutting tools or the iron of our magnets, the basis of all commercial electricity.
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  • Buyers of certain excellent classes of Swedish iron have been said to object even to the substitution of electricity for water-power as a means of driving the machinery of the forge.
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  • This charge is heated, like the filaments of a common household electric lamp, by the resistance which it offers to the passage of a current of electricity induced in it by means of the core C and the frame EEE.
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  • But this is rarely expedient, because electricity is so expensive that it should be used for doing only those things which cannot be accomplished by any other and cheaper means.
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  • We are now in a position to understand why electricity should be used as a source of heat in making molten steel.
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  • Thus we see that the purification in these electric furnaces has nothing to do with electricity.
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  • The electricity is solely a source of heat, free from the faults of the older sources which for certain purposes it now replaces.
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  • Its physical and chemical properties have been the subject of much study, and have a special interest in view of the extraordinary difference between the physical characters of the diamond and those of graphite (blacklead) or charcoal, with which it is chemically identical, and into which it can be converted by the action of heat or electricity.
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  • Diamond differs from graphite in being a bad conductor of electricity: it becomes positively electrified by friction.
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  • We thus see that radium is continually losing matter and energy as electricity; it is also losing energy as heat, for, as was observed by Curie and Laborde, the temperature of a radium salt is always a degree or two above that of the atmosphere, and they estimated that a gramme of pure radium would emit about 100 gramme-calories per hour.
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  • It is a garrison town, with streets lighted by electricity, a high-school or gymnasium, a prefecture and a court of first instance.
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  • Weber's hypothesis of electric atoms, capable of diffusing through metallic bodies and conductors of electricity, but capable of vibration only in non-conductors, it is possible that the ultimate mechanism of conduction may be reduced in all cases to that of diffusion in metallic bodies or internal radiation in dielectrics.
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  • Two years later he first tried the effect of electro-puncture of the muscles on a patient under his care, and from this time on devoted himself more and more to the medical applications of electricity, thereby laying the foundation of the modern science of electro-therapeutics.
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  • He published over fifty volumes containing his researches on muscular and nervous diseases, and on the applications of electricity both for diagnostic purposes and for treatment.
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  • The general public were content to find the explanation of the movements in spirits, animal magnetism, odic force, galvanism, electricity, or even the rotation of the earth.
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  • In 1876 he exhibited an apparatus embodying the results of his studies in the transmission of sound by electricity, and this invention, with improvements and modifications, constitutes the modern commercial telephone.
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  • Usually the electric potential near the ground is positive compared to the earth and increases with the height (see Atmospheric Electricity).
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  • Alumina is treated at works near Foyers in the shire of Inverness, where abundant water power enables electricity to be generated cheaply.
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  • The city is provided with tramway and telephone services, the streets are lighted with gas and electricity, and telegraph communication with the outside world is maintained by means of the West Coast cable, which lands at the small port of Santa Elena, on the Pacific coast, about 65 m.
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  • He was elected town councillor of the famous Great Western railway centre, Swindon, and became chairman of the Finance Committee and of the Electricity and Tramways Committee.
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  • Perhaps the most original, and certainly the most permanent in their influence, were his memoirs on the theory of electricity and magnetism, which virtually created a new branch of mathematical physics.
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  • Its industrial importance is shown by the fact that it is the site of the West Swiss technical institute, which has departments for instruction in watch-making, in electricity, in engraving and chasing, and in subjects relating to railway, postal and telegraph matters.
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  • No better testimony to the value of the quaternion method could be desired than the constant use made of its notation by mathematicians like Clifford (in his Kinematic) and by physicists like ClerkMaxwell (in his Electricity and Magnetism).
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  • Near Douglas, in Converse county, there is a reinforced concrete dam, impounding the waters of Laprele Creek, to furnish water for over 30,000 acres, and power for transmitting electricity.
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  • If an electrified body is held near the gold-leaf electroscope the leaves diverge with electricity of the same sign as that of the body being tested.
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  • If the electroscope is insulated once more and the electrified body removed, the leaves again diverge with electricity of the opposite sign to that of the body being tested.
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  • If the electrified body is touched against the upper plate whilst at the same time the lower plate is put to earth, the condenser formed of the two plates and the film of air or varnish becomes charged with positive electricity on the one plate and negative on the other.
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  • Volta made use of such an electroscope in his celebrated experiments (1790-1800) to prove that metals placed in contact with one another are brought to different potentials, in other words to prove the existence of so-called contact electricity.
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  • Starting from an experiment, narrated by Priestley, in which John Warltire fired a mixture of common air and hydrogen by electricity, with the result that there was a diminution of volume and a deposition of moisture, Cavendish burnt about two parts of hydrogen with five of common air, and noticed that almost all the hydrogen and about one-fifth of the common air lost their elasticity and were condensed into a dew which lined the inside of the vessel employed.
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  • In electricity Abel studied the construction of electrical fuses and other applications of electricity to warlike purposes, and his work on problems of steel manufacture won him in 1897 the Bessemer medal of the Iron and Steel Institute, of which from 1891 to 1893 he was president.
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  • Helsingfors was without tramcars, cabs, gas and electricity; no shops except provision shops were open; public departments, schools and restaurants were closed.
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  • The two great branches of electrical theory which concern the phenomena of electricity at rest, or " frictional " or " static " electricity, and of electricity in motion, or electric currents, are treated in two separate articles, Electrostatics and Electrokinetics.
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  • The phenomena attendant on the passage of electricity through solids, through liquids and through gases, are described in the article Electric conduction, and also Electrolysis, and the propagation of electrical vibrations in Electric Waves.
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  • The general principles of electrical engineering will be found in Electricity Supply, and further details respecting the generation and use of electrical power are given in such articles as Dynamo; Motors, Electric; Transformers; Accumulator; Power Transmission: Electric; Traction; Lighting: Electric; Electrochemistry and Electrometallurgy.
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  • The term " electricity " is applied to denote the physical agency which exhibits itself by effects of attraction and repulsion when particular substances are rubbed or heated, also in certain chemical and physiological actions and in connexion with moving magnets and metallic circuits.
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  • The subsequent history of electricity may be divided into four well-marked periods.
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  • We shall sketch briefly the historical progress during these various stages, and also the growth of electrical theories of electricity during that time.
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  • Robert Boyle added many new facts and gave an account of them in his book, The Origin of Electricity.
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  • Stephen Gray (1696-1736) noticed in 1720 that electricity could be excited by the friction of hair, silk, wool, paper and other bodies.
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  • In 1729 Gray made the important discovery that some bodies were conductors and others nonconductors of electricity.
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  • He also discovered that a body charged with positive or negative electricity repels a body free to move when the latter is charged with electricity of like sign, but attracts it if it is charged with electricity of opposite sign, i.e.
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  • For a very full list of the papers and works of these early electrical philosophers, the reader is referred to the bibliography on Electricity in Dr Thomas Young's Natural Philosophy, vol.
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  • Watson carried out elaborate experiments to discover how far the electric discharge of the jar could be conveyed along metallic wires and was able to accomplish it for a distance of 2 m., making the important observation that the electricity appeared to be transmitted instantaneously.
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  • He argued that electricity is not created by friction, but merely collected from its state of diffusion through other matter by which it is attracted.
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  • He asserted that the glass globe, when rubbed, attracted the electrical fire, and took it from the rubber, the same globe being disposed, when the friction ceases, to give out its electricity to any body which has less.
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  • In the case of the charged Leyden jar, he asserted that the inner coating of tinfoil had received more than its ordinary quantity of electricity, and was therefore electrified positively, or plus, while the outer coating of tinfoil having had its ordinary quantity of electricity diminished, was electrified negatively, or minus.
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  • Hence the cause of the shock and spark when the jar is discharged, or when the superabundant or plus electricity of the inside is transferred by a conducting body to the defective or minus electricity of the outside.
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  • This theory of the Leyden phial Franklin supported very ingeniously by showing that the outside and the inside coating possessed electricities of opposite sign, and that, in charging it, exactly as much electricity is added on one side as is subtracted from the other.
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  • The abundant discharge of electricity by points was observed by Franklin is his earliest experiments, and also the power of points to conduct it copiously from an electrified body.
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  • Hence he was furnished with a simple method of collecting electricity from other bodies, and he was enabled to perform those remarkable experiments which are chiefly connected with his name.
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  • Previously to the year 1750, Franklin drew up a statement, in which he showed that all the general phenomena and effects which were produced by electricity had their counterparts in lightning.
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  • After waiting some time for the erection of a spire at Philadelphia, by means of which he hoped to bring down the electricity of a thunderstorm, he conceived the idea of sending up a kite among thunder-clouds.
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  • The suspended key gave a spark on the application of his knuckle, and when the string had become wet with the rain the electricity became abundant.
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  • In subsequent trials with another apparatus, he found that the clouds were sometimes positively and sometimes negatively electrified, and so demonstrated the perfect identity of lightning and electricity.
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  • The electricity of a hovering or a passing cloud would thus be carried off slowly and silently; and if the cloud was highly charged, the lightning would strike in preference the elevated conductors.'
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  • The most important of Franklin's electrical writings are his Experiments and Observations on Electricity made at Philadelphia, 1 75 1 - 1 754; his Letters on Electricity; and various memoirs and letters in the Phil.
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  • John Canton (1718-1772) made the important contribution to knowledge that electricity of either sign could be produced on nearly any body by friction with appropriate substances, and that a rod of glass roughened on one half was excited negatively in the rough part and positively in the smooth part by friction with the same rubber.
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  • The subject of pyro-electricity, or the power possessed by some minerals of becoming electrified when merely heated, and of exhibiting positive and negative electricity, now began to attract notice.
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  • He found that the electricity of the tourmaline decreased rapidly from the summits or poles towards the middle of the crystal, where it was imperceptible; and he discovered that if a tourmaline is broken into any number of fragments, each fragment, when excited, has two opposite poles.
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  • Adopting the hypothesis of two fluids, Coulomb investigated experimentally and theoretically the distribution of electricity on the surface of bodies by means of his proof plane.
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  • He determined the law of distribution between two conducting bodies in contact; and measured with his proof plane the density of the electricity at different points of two spheres in contact, and enunciated an important law.
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  • He ascertained the distribution of electricity among several spheres (whether equal or unequal) placed in contact in a straight line; and he measured the distribution of 2 In 1878 Clerk Maxwell repeated Cavendish's experiments with improved apparatus and the employment of a Kelvin quadrant electrometer as a means of detecting the absence of charge on the inner conductor after it had been connected to the outer case, and was thus able to show that if the law of electric attraction varies inversely as the nth power of the distance, then the exponent n must have a value of 2 t Isua.
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  • He found also that the dissipation of electricity along insulators was chiefly owing to adhering moisture, but in some measure also to a slight conducting power.
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  • It was then found that when the end plates of Volta's pile were connected to an electroscope the leaves diverged either with positive or negative electricity.
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  • In 1806 Davy communicated to the Royal Society of London a celebrated paper on some " Chemical Agencies of Electricity," and after providing himself at the Royal Institution of London with a battery of several hundred cells, he announced in 1807 his great discovery of the electrolytic decomposition of the alkalis, potash and soda, obtaining therefrom the metals potassium and sodium.
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  • In it Oersted describes the action he considers is taking place around 2 Faraday discussed the chemical theory of the pile and arguments in support of it in the 8th and 16th series of his Experimental Researches on Electricity.
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  • In 1821 Michael Faraday (1791-1867), who was destined later on to do so much for the science of electricity, discovered electromagnetic rotation, having succeeded in causing a wire conveying a voltaic current to rotate continuously round the pole of a permanent magnet.
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  • P. Joule found that magnetization did not increase proportionately with the current, but reached a maximum (Sturgeon's Annals of Electricity, 1839, 4).
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  • Turning to practical applications of electricity, we may note that electric telegraphy took its rise in 1820, beginning with a suggestion of Ampere immediately after Oersted's discovery.
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  • Weber had already laid the foundations of the absolute system of electric and magnetic measurement, and proved that a quantity of electricity could be measured either by the force it exercises upon another static or stationary quantity of electricity, or magnetically by the force this quantity of electricity exercises upon a magnetic pole when flowing through a neighbouring conductor.
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  • Maxwell's electric and magnetic ideas were gathered together in a great mathematical treatise on electricity and magnetism which was published in 1873.1 This book stimulated in a most remarkable degree theoretical and practical research into the phenomena of electricity and magnetism.
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  • This early work indicated that whilst there were a number of cases in which the square 1 A Treatise on Electricity and Magnetism (2 vols.), by James Clerk Maxwell, sometime professor of experimental physics in the university of Cambridge.
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  • Turning now to the theory of electricity, we may note the equally remarkable progress made in 300 years in scientific insight into the nature of the agency which has so recast the face of human society.
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  • Its duplex character, and the fact that the electricity produced by rubbing glass and vitreous substances was different from that produced by rubbing sealing-wax and resinous substances, seemed to necessitate the assumption of two kinds of electric fluid; hence there arose the conception of positive and negative electricity, and the two-fluid theory came into existence.
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  • The positive and negative electrifications of the two coatings of the Leyden jar were therefore to be regarded as the result of a transformation of something called electricity from one coating to the other, by which process a certain measurable quantity became so much less on one side by the same amount by which it became more on the other.
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  • Electric attractions and repulsions were, however, regarded as differential actions in which the mutual repulsion of the particles of electricity operated, so to speak, in antagonism to the mutual attraction of particles of matter for one another and of particles of electricity for matter.
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  • The notion then formed of the nature of electrification was something as follows: All bodies were assumed to contain a certain quantity of a so-called neutral fluid made up of equal quantities of positive and negative electricity, which when in this state of combination neutralized one another's properties.
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  • Canton (1 753, 1 754) When, for instance, a positively electrified body was found to induce upon another insulated conductor a charge of negative electricity on the side nearest to it, and a charge of positive electricity on the side farthest from it, this was explained by saying that the particles of each of the two electric fluids repelled one another but attracted those of the positive fluid.
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  • The two-fluid theory may be said to have held the field until the time when Faraday began his researches on electricity.
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  • Faraday's notion as to the nature of electrification, therefore, about the middle of the 19th century came to be something as follows: - He considered that the so-called charge of electricity on a conductor was in reality nothing on the conductor or in the conductor itself, but consisted in a state of strain or polarization, or a physical change of some kind in the particles of the dielectric surrounding the conductor, and that it was this physical state in the dielectric which constituted electrification.
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  • In the 13th series of his Experimental Researches on Electricity he discussed the relation of a vacuum to electricity.
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  • Furthermore his electrochemical investigations, and particularly his discovery of the important law of electrolysis, that the movement of a certain quantity of electricity through an electrolyte is always accompanied by the transfer of a certain definite quantity of matter from one electrode to another and the liberation at these electrodes of an equivalent weight of the ions, gave foundation for the idea of a definite atomic charge of electricity.
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  • Berzelius early in the 19th century had advanced the hypothesis that chemical combination was due to electric attractions between the electric charges carried by chemical atoms. The notion, however, that electricity is atomic in structure was definitely put forward by Hermann von Helmholtz in a well-known Faraday lecture.
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  • Helmholtz says: " If we accept the hypothesis that elementary substances are composed of atoms, we cannot well avoid concluding that electricity also is divided into elementary portions which behave like atoms of electricity."
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  • The theory of the ionization of salts in solution has raised much discussion amongst chemists, but the general fact is certain that electricity only moves through liquids in association with matter, and simultaneously involves chemical dissociation of molecular groups.
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  • Discharge through Gases.-Many eminent physicists had an instinctive feeling that the study of the passage of electricity through gases would shed much light on the intrinsic nature of electricity.
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  • It has long been known that air and other gases at the pressure of the atmosphere were very perfect insulators, but that when they were rarefied and contained in glass tubes with platinum electrodes sealed through the glass, electricity could be passed through them under sufficient electromotive force and produced a luminous appearance known as the electric glow discharge.
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  • The mineral is a non-conductor of electricity; it is unattacked by acids with the exception of hydrofluoric acid, and is only slightly dissolved by solutions of caustic alkalis.
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  • The dockyard is lighted by electricity, so that work can be carried on by night as well as day.
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  • It is a non-conductor of electricity.
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  • He was the first in England to verify Benjamin Franklin's hypothesis of the identity of lightning and electricity, and he made several important electrical discoveries.
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  • The river Pescara and its tributary the Tirino form an important source of power for generating electricity.
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  • In many European cities the supply of water, even for domestic purposes, is given through ordinary water meters, and paid for, according to the meter record, much in the same manner as a supply of gas or electricity.
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  • His name is not associated with any discovery of the first order, but his researches (especially in connexion with electricity) were remarkable for their number and variety.
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  • Among the more valuable manufactures are: newspapers, books, &c. ($924,495 in 1905), malt liquors, confectionery, flour, foundry and machine-shop products, dairy products, salt, knit goods, mattresses, sugar, cement, &c. Electricity is largely used in the newer factories, the power being derived from Ogden river, near Ogden, about 35 m.
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  • Electricity had even a greater effect on communication than steam oii locomotion; and electricity, as a practical invention, had its origin in the reign.
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  • Aepinus is best known by his researches, theoretical and experimental, in electricity and magnetism, and his principal work, Tentamen Th