We're in the middle of an electrical storm.
Covers needed to be put on the electrical outlets and the windows still held their tags.
When this has been done an electrical test is applied, and if the original fracture is between ship and shore the heaving in of cable will continue until the end comes on board.
Experiments very similar to these of Edison were made by Elisha Gray of Boston, Mass., and described by him in papers communicated to the American Electrical Society in 1875 and 1878.
Our internal electrical system works by using cells that have built up electrical gradient or energy that can be given off to other cells by direct transfer.
After the cable has been again subjected to the proper electrical tests and found to be in perfect condition, the ship is taken to the place where the shore end is to be landed.
In the electrical building we examined the telephones, autophones, phonographs, and other inventions, and he made me understand how it is possible to send a message on wires that mock space and outrun time, and, like Prometheus, to draw fire from the sky.
The principal manufactures of East Orange are electrical machinery, apparatus, and supplies (the factory of the Crocker-Wheeler Co.
Exchange From the Post Office Electrical Engineers' Journal.
The end is taken into the testing room in the cable-house and the conductor connected with the testing instruments, and, should the electrical tests continue satisfactory, the ship is put on the proper course and steams slowly ahead, paying out the cable over her stern.
Weissenfels manufactures machinery, ironware, paper and other goods, and has an electrical power-house.
Meyer, The British State Telegraphs (London, 1907); The " Electrician " Electrical Trades Directory; E.
This strain corresponds to the electrical charging of the antenna.
2+f From the Post Office Electrical Engineers' Journal.
Hitherto the large bill for electric energy has debarred the general use of electrical heating, in spite of its numerous advantages.
He also investigated electrical endosmosis and the electrical resistance of electrolytes.
The availability of the energy of electrical separation in a charged Leyden jar is also limited only by the resistance of conductors, in virtue of which an amount of heat is necessarily produced, which is greater the less the time occupied in discharging the jar.
The antenna has at one moment a static electrical charge distributed upon it, and lines of electric force stretch from it to the surrounding earth.
The result, was in Helmholtz's words, to establish beyond doubt that ordinary light consists of electrical vibrations in an all-pervading ether which possesses the properties of an insulator and of a magnetic medium.
The following branches have especially felt his influence: - chemical physics, capillarity and viscosity, theory of gases, flow of liquids, photography, optics, colour vision, wave theory, electric and magnetic problems, electrical measurements, elasticity, sound and hydrodynamics.
Dr. Bell went with us himself to the electrical building, and showed us some of the historical telephones.
How could it be so cold during an electrical storm?
2940, Dr Repsold proposed a method of meridian observing which consists in causing a web to follow the image of a star in transit by motions communicated by the observer's hands alone, whilst electrical contacts on the drum of the micrometer screw register on the chronograph the instants corresponding to known intervals from the line of collimation.
At the receiving station electrical mechanisms record the signals once more as perforations in a paper strip forming an exact replica of the transmitting tape.
As the direction and intensity of this induced current are a function of the position of the second coil in its field, and as this position is determined by its mechanical connexion with the recorder coil, it is evident that, by a suitable choice of the electrical elements of the second coil and its alternating field, the indications on the siphon recorder can be magnified to any reasonable extent.
The electrical condition of the cable was then excellent, but unfortunately the electrician in charge, Wildman Whitehouse, conceived the wrong idea that it should be worked by currents of high potential.
The special electrical engineering arrangements employed at the outset for this first electric wave power station required to create the oscillations of the desired power were designed for Marconi by J.
The vast number of microphonic contacts present give rise to very strong electrical undulations, and hence to a loud sound.
When one of two subscribers connected together by this arrangement talks, the Exchange From the Post Office Electrical Engineers' Journal.
These two circuits are syntonized so that the closed or condenser circuit and the open or antenna circuit are adjusted to have, when separate, the same natural electrical time of vibration.
The electrical connexions of the instrument as arranged for actual use are also illustrated in the figure.
Garcke, Manual of Electrical Undertakings.
15599 of 1903; also a lecture given in London, November 27, 1906, " On a Method of producing undamped Electrical Oscillations and their employment in Wireless Telegraphy," Electrician, 1906, 58, p. 166.
.1 From the Post Office Electrical Engineers' Journal.
The scientific study of electric wave telegraphy has necessitated the introduction of many new processes and methods of electrical measurement.
The difficulty experienced is that of securing a good electrical contact under the very slight pressure obtainable from an instrument excited by attenuated arrival-currents.
Since in all cases of From the Electrical Review, by permission of the Editors.
Up to 1895 or 1896 the suggestions for wireless telegraphy which had been publicly announced or tried can thus be classified under three or four divisions, based respectively upon electrical conduction through the soil or sea, magnetic induction through space, combinations of the two foregoing, and lastly, electrostatic induction.
It is then placed in a tank of water and kept at a certain fixed temperature, usually 75° F., until it assumes approximately a constant electrical state.
- a From the Post Office Electrical Engineers' Journal.
perfect electrical contact between the steel and mercury for low voltage currents, but when electric oscillations were passed through the junction it was pierced and good electrical contact established as long as the oscillations continued.
The earliest practical trial of electrical telegraphy was made in 1837 on the London and North Western Railway, and the first public line under the patent of Wheatstone and Cooke was laid from Paddington to Slough on the Great Western Railway in 1843.
This condenser is charged electrically and then suddenly discharged and violent electrical oscillations are set up in it, that is to say, electricity rushes to and fro between the antenna and the earth.
The lower end e of the cable in the tank T is taken to the testing room, so that continuous tests for electrical condition can be made.
The modus operandi is briefly as follows: The position of the fracture is determined by electrical tests from both ends, with more or less accuracy, depending on the nature of the fracture, but with a probable error not exceeding a few miles.
Poulsen's method of producing continuous or undamped electrical waves has been applied by him in radio-telegraphy.
The ink is electrified by a small induction electrical machine E placed on the top of the instrument; this causes it to fall in very minute drops from the open end of the siphon tube upon the brass table or the paper slip passing over it.
This corresponds to the electrical discharge of the antenna, and the subsequent string vibrations to the electrical vibrations.
The oil film prevented 1 See Electrical Review, 1902, 51, p. 968.
The sizes of copper wire employed have weights of too, 150, 200 and 400 lb per statute mile, and have electrical resistances (at 60° F.) of 8.782, 5.8 55, 4.39 1 and 2.195 standard ohms respectively.
He discovered a fact subsequently rediscovered by others, that a tube of metallic filings, loosely packed, was sensitive to electric sparks made in its vicinity, its electrical resistance being reduced, and he was able to detect effects on such a tube connected to a battery and telephone at a distance of 500 yds.'
The bottle was held in the hand, and the nail presented to the prime conductor of an electrical machine.
For the purposes of wireless telegraphy, when large condensers are required, the ordinary Leyden jar occupies too much space in comparison with its electrical capacity, and hence the best form of con denser consists of a number of sheets of crown glass, each partly coated on both sides with tin foil.
1900), who quotes the results of similar experiments made at McGill College in 1897, but gives an entirely different interpretation, based on a direct measurement of the - specific heat at 100° C. by an electrical method.
The telautograph is on a similar principle to the Cowper apparatus, the motion of the transmitting pencil or stylus used in writing being resolved by a system of levers into two component rectilinear motions, which are used to control and vary the currents in two distinct electrical circuits.
Garcke, Manual of Electrical Undertakings (1896-1908).
The various electrical phenomena of plants also are obscure.
Hartog has endeavoured to show that it can only he formed by a dual force, analagous to that of magnetism, the spindle-fibi es being comparable to the lines of force in a magnetic field and possibly due to electrical differences in the cell.
The chief industries are the making of sugar and shoes, and there are also electrical works and saw-mills.
Kelway invented an electrical log in 1876.
In certain respects, on the other hand, America has gone further than the United Kingdom, especially in the matter of automatic signalling, and in the operating of points and signals by electrical power or air-pressure instead of manual labour.
The fundamental difference between the two methods is that while the mechanical energy developed by a steam engine is in the first case applied directly to the driving-axle of the locomotive, in the second case it is transformed into electrical energy, transmitted over relatively long distances, and retransformed into mechanical energy on the driving-axles of the train.
In most of the systems that have been proposed this result is attained by electrical regulation; in one, however, a mechanical method is adopted, the dynamo being so' hung that it allows the driving belt to slip when the speed of the axle exceeds a certain limit, the armature thus being rotated at an approximately constant speed.
About the same time appeared his elaborate memoir, " On Faraday's Lines of Force," in which he gave the first indication of some of those extraordinary electrical investigations which culminated in the greatest work of his life.
One of Maxwell's last great contributions to science was the editing (with copious original notes) of the Electrical Researches of the Hon.
When the first system then is transformed into the second, the excess of energy which the former possesses must appear in the shape of heat, light, electrical energy, mechanical energy, &c. It is for the most part a simple matter to obtain the excess of energy entirely in the form of heat, the amount of which is easily susceptible of measurement, and thus the existence of thermochemistry as a practical science is rendered possible.
For ordinary combustions compressed oxygen is used, so that the combustible substance burns almost instantaneously, the action being induced by means of some electrical device which can be controlled from without the calorimeter.
The saw-fishes, Pristidae, the electrical rays, Torpedinae, and ordinary rays and skates, are also found in considerable numbers.
Among the city's manufactures are oxide of tin and other chemicals, iron and steel, leather goods, automobiles and bicycles, electrical and telephone supplies, butted tubing, gas engines, screws and bolts, silk, lace and hosiery.
In 1901 the Copley medal of the Royal Society of London was awarded him as being "the first to apply the second law of thermodynamics to the exhaustive discussion of the relation between chemical, electrical and thermal energy and capacity for external work."
($11,791,223), electrical machinery, apparatus and supplies ($11,019,235), paper and wood pulp ($10,961,527) and refined petroleum ($10,948,864).
An instrument of the latter type of considerable accuracy was designed by Lord Kelvin for the British Board of Trade Electrical Laboratory, and it is there used as the principal standard ampere balance.
Thomson), " New Standard and Inspectional Electrical Measuring Instruments," Proc. Soc. Telegraph Engineers, 1888, 17, p. 540; J.
Fleming, A Handbook for the Electrical Laboratory and Testing Room (2 vols., London, 1901, 1903); G.D.Aspinall Parr, Electrical Measuring Instruments (Glasgow, 1903); J.
For example, the physicist determines the density, elasticity, hardness, electrical and thermal conductivity, thermal expansion, &c.; the chemist, on the other hand, investigates changes in composition, such as may be effected by an electric current, by heat, or when two or more substances are mixed.
Transformations of electrical into chemical energy are witnessed in the processes of electrolysis (q.v.; see also Electrochemistry and Electrometallurgy).
Other thriving trades include the glass-works on the shore, pottery-works in the "auld toon," dye-works and a factory for the making of electrical appliances.
Here is situated the Dreher brewery, the largest in the monarchy; and there are also important smelting and iron works, cotton-spinning, factories of electrical plant, &c. The meeting at Schwechat of the emperor Leopold I.
At the age of fourteen he entered Yale College, where he graduated in 1810 and where under the instruction of Jeremiah Day and Benjamin Silliman he received the first impulse towards electrical studies.
There was nothing electrical in Thoreau's intercourse with his fellow men; he gave off no spiritual sparks.
The most important manufactures are iron and steel, carriage hardware, electrical supplies, bridges, boilers, engines, car wheels, sewing machines, printing presses, agricultural implements, and various other commodities made wholly or chiefly from iron and steel.
Nitrogen is always being synthesized from the atmosphere (by plants, and by electrical discharges which combine nitrogen and oxygen), and this combined nitrogen is either utilized by land organisms or is washed down into the sea in the water of the rivers.
(I) In very dilute solutions of simple substances, where only one kind of dissociation is possible and the dissociation of the ions is complete, the number of pressure-producing particles necessary to produce the observed osmotic effects should be equal to the number of ions given by a molecule of the salt as shown by its electrical properties.
5.08 At the concentration used by Loomis the electrical conductivity indicates that the ionization is not complete, particularly in the case of the salts with divalent ions in the second list.
The freezing point curve usually lies below the electrical one, but approaches it as dilution is increased.2 Returning once more to the consideration of the first relation, which deals with the comparison between the number of ions and the number of pressure-producing particles in dilute solution, one caution is necessary.
The electrical phenomena show that there are two ions to the molecule, and that these ions are electrically charged.
It' would be possible for a body in solution to be dissociated into non-electrical parts, which would give osmotic pressure effects twice or three times the normal value, but, being uncharged, would not act as ions and impart electrical conductivity to the solution.
It is possible that in complicated organic substances we might have two kinds of dissociation, electrical and non-electrical, occurring simultaneously, while the possibility of the association of molecules accompanied by the electrical dissociation of some of them into new parts should not be overlooked.
It is probable that the electrical effects constitute the strongest arguments in favour of the theory.
the electrical conductivities of normal solutions of the acids have been tabulated.
Nevertheless, the remarkable general agreement of the numbers in the four columns is quite enough to show the intimate connexion between chemical activity and electrical conductivity.
As an example of a fairly constant cell we may take that of Daniell, which consists of the electrical arrangement - zinc zinc sulphate solution copper sulphate solution copper, - the two solutions being usually separated by a pot of porous earthenware.
If the chemical changes which occur in the cell were allowed to take place in a closed vessel without the performance of electrical or other work, the change in energy would be measured by the heat evolved.
On the other hand, we may imagine the processes due to the electrical transfer to be reversed by an osmotic operation.
Solvent may be supposed to be squeezed out from the solution which has become more dilute through a semi-permeable wall, and through another such wall allowed to mix with the solution which in the electrical operation had become more concentrated.
Again, we may calculate the osmotic work done, and, if the whole cycle of operations be supposed to occur at the same temperature, the osmotic work must be equal and opposite to the electrical work of the first operation.
The result of the investigation shows that the electrical work Ee is given by the_equation Ee =1 where v is the volume of the solution used and p its osmotic pressure.
Caoutchouc is a bad conductor of heat and electricity, and alone or mixed with other materials is employed as an electrical insulator.
Large metallic surfaces (especially external surfaces) are sometimes plated by means of a "doctor," which, in its simplest form, is a brush constantly wetted with the electrolyte, with a wire anode buried amid the hairs or bristles; this brush is painted slowly over the surface of the metal to be coated, which must be connected to the negative terminal of the electrical generator.
The most extensive application of mica at the present day is for electrical purposes.
Phlogopite is rarely found as colourless transparent sheets and is therefore almost exclusively used for electrical purposes.
He was knighted in 1897, and received the Royal (1875), Davy (1888), and Copley (1904) medals of the Royal Society, besides filling the offices of president of the Chemical Society and of the Institution of Electrical Engineers.
Magnetic induction, like other fluxes such as electrical, thermal or fluid currents, is defined with reference to an area; it satisfies the same conditions of continuity as the electric current does, and in isotropic media it depends on the magnetic force just as the electric current depends on the electromotive force.
The magnetic flux per square centimetre at any point (B, B, or 0) is briefly called the induction, or, especially by electrical engineers, the flux-density.
The ballistic method is largely employed for determining the relation of induction to magnetizing force in samples of the iron and steel used in the manufacture of electrical machinery, and especially for the observation of hysteresis effects.
But though a formula of this type has no physical significance, and cannot be accepted as an equation to the actual curve of W and B, it is, nevertheless, the case that by making the index e =1.6, and assigning a suitable value to r t, a formula may be obtained giving an approximation to the truth which is sufficiently close for the ordinary purposes of electrical engineers, especially when the limiting value of B is neither very great nor very small.
Several pieces of apparatus have been invented for comparing the magnetic quality of a sample with that of a standard iron rod by a zero method, such as is employed in the comparison of electrical resistances by the Wheatstone bridge.
The fact, which will be referred to later, that the electrical resistance of bismuth is very greatly affected by a magnetic field has been applied in the construction of apparatus for measuring field intensity.
Abrupt alterations, take place in its density, specific heat, thermo-electric quality, electrical conductivity, temperature-coefficient of electrical resistance, and in some at least of its mechanical properties.
magnetizable it is a hard steel, having a specific electrical resistance of o 000052; when non-magnetizable it is an extremely soft, mild steel, and its specific resistance is 0 000072.
The process of electric conduction in metals consists in the movement of detached electrons, and many other phenomena, both electrical and thermal, can be more or less completely explained by their agency.
They relate almost entirely to electrical phenomena, such as the magnetic rotation of light, the action of gas batteries, the effects of torsion on magnetism, the polarization of electrodes, &c., sufficiently complete accounts of which are given in Wiedemann's Galvanismus.
It may be convenient to use the terms "vitality" and "vital force" to denote the causes of certain great groups of natural operations, as we employ the names of "electricity" and "electrical force" to denote others; but it ceases to be proper to do so, if such a name implies the absurd assumption that "electricity" and "vitality" are entities playing the part of efficient causes of electrical or vital phenomena.
Its coefficient of linear expansion between 0° and 100° is 0.002717; its specific heat 0.0562; its thermal and electrical conductivities are 145 to 152 and '14.5 to 140.
Stimuli comprise chemical, mechanical, thermal, photic and electrical changes in the environment of the organism.
His work was mainly, though not exclusively, electrical, and his services were in great demand as an expert witness in patent cases.
In 1890 he was appointed director of the Siemens laboratory at King's College, London, with the title of professor of electrical engineering.
A student of mining must receive thorough instruction in geology; he must study mining as practised in different countries, and the metallurgical and mechanical treatment of minerals; and he should have an engineering education, especially on mechanical and electrical lines.
Electrical furnaces have not as yet been employed for ordinary glass-making on a commercial scale, but the electrical plants which have been erected for melting and moulding quartz suggest the possibility of electric heating being employed for the manufacture of glass.
In most modern works the greater part of these operations, as well as the actual rolling of the glass, is carried out by mechanical means, steam power and subsequently electrical power having been successfully applied to this purpose; the handling of the great weights of glass required for the largest sheets of plate-glass which are produced at the present time would, indeed, be impossible without the aid of machinery.
The method of electrical images will enable the stream function, )' to be inferred from a distribution of doublets, finite in number when the surface is composed of two spheres intersecting at an angle 7r/m, where m is an integer (R.
In 1785 appeared his Recherches theoriques et experimentales sur la force de torsion et sur l'elasticite des fils de metal, &c. This memoir contained a description of different forms of his torsion balance, an instrument used by him with great success for the experimental investigation of the distribution of electricity on surfaces and of the laws of electrical and magnetic action, of the mathematical theory of which he may also be regarded as the founder.
His talent for electrical engineering was soon shown, and his progress was rapid; so that in 1852 he was appointed engineer to the Magnetic Telegraph Company, and in that capacity superintended the laying of lines in various parts of the British Isles, including in 1853 the first cable between Great Britain and Ireland, from Portpatrick to Donaghadee.
In conjunction with Josiah Latimer Clark, with whom he entered into partnership in 1861, he invented improved methods of insulating submarine cables, and a paper on electrical standards read by them before the British Association in the same year led to the establishment of the British Association committee on that subject, whose work formed the foundations of the system still in use.
The fact that energy is being used at so high a rate as Too H.P. on so small a charge of material sufficiently indicates that the furnace is only used for experimental work, or for the fusion of metals which, like tungsten or chromium, can only be melted at temperatures attainable by electrical means.
Among the other manufactories are flouring and grist mills, planing mills, foundries, and factories for making agricultural implements, United States mail boxes, furniture, pianos, organs, automobiles, toys and electrical supplies.
were: combined textiles (not including flax, hemp and jute products) in 1900, $77,998,396; in 1905, $103,096, 311; foundry and machine shop products in 1900, $13,269,086; in 1905, $16,338,512; woollen goods in 1900, $5,330,550; in 1905, $8,163,167; rubber boots and shoes in 1 9 00, $8,034,417; electrical machinery, apparatus and supplies in 1900, $5,113,292; in 1905, $5,435,474; silversmithing and silverware in 1900, $4,249,190; in 1905, $5,323,264; gold and silver, reducing and refining (not from ore) in 1900, $3,484,454; in 1905, $4,260,698; cotton small wares in 1900, $2,379,500; in 1 905, $3,944, 60 7; hosiery and knit goods in 1900, $2,713,850; in 1905, $3,344,655; silk and silk goods in 1900, $1,311,333; in 1905, $2,555,986.
For the theory and elemental laws of electro-deposition see Electrolysis; and for the construction and use of electric generators see Dynamo and Battery: Electric. The importance of the subject may be gauged by the fact that all the aluminium, magnesium, sodium, potassium, calcium carbide, carborundum and artificial graphite, now placed on the market, is made by electrical processes, and that the use of such processes for the refining of copper and silver, and in the manufacture of phosphorus, potassium chlorate and bleach, already pressing very heavily on the older non-electrical systems, is every year extending.
ft., at 3 volts, passing between platinum electrodes, he attained to a current-efficiency of 52%, and each (British) electrical horse-power hour was equivalent to a production of 1378.5 grains of potassium chlorate.
Rotating zinc cathodes were used, with scrapers to prevent the accumulation of a layer of insoluble magnesium compounds, which would otherwise increase the electrical resistance beyond reasonable limits.
Depending on the fact that the electrical conductivity of a metallic conductor is decreased by heat, it consists of two strips of platinum, arranged to form the two arms of a Wheatstone bridge; one strip being exposed to a source of radiation from which the other is shielded, the heat causes a change in the resistance of one arm, the balance of the bridge is destroyed, and a deflection is marked on the galvanometer.
The electrical conductivity of a metal is often very much decreased by alloying with it even small quantities of another metal.
When a pure metal is cooled to a very low temperature its electrical conductivity is greatly increased, but this is not the case with an alloy.
Manganese not only forms with iron several alloys of great interest, but alloyed with copper it is used for electrical purposes, as an alloy can thus be obtained with an electrical resistance that does not alter with change of temperature; this alloy, called manganin, is used in the construction of resistance-boxes.
Among the manufactures are brass and copper work, wire for electrical uses, foundry and machine-shop products, locomotives, knit goods, tin cans and canned goods (especially vegetables).
ELECTROSTATICS, the name given to that department of electrical science in which the phenomena of electricity at rest are considered.
The reader possessed of no previous knowledge of electrical phenomena will best appreciate the meaning of the terms employed by the aid of a few simple experiments.
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.
To avoid unnecessary complications we shall assume this latter condition in all the following discussion, which is equivalent simply to assuming that all our electrical measurements are made in air or in vacuo.
(i) Electrical Equilibrium and Potential.
§ 74a; also Electrical Researches of the Hon.
this envelope should be of solid metal; a cage made of fine metal wire gauze which permits objects in its interior to be seen will yet be a perfect electrical screen for them.
In fact it is curious to note how large an opening may be made in a vessel which yet remains for all electrical purposes " a closed conductor."
We must next consider the quality of a conductor called its electrical capacity.
Dielectric constant.-Since all electric charge consists in a state of strain or polarization of the dielectric, it is evident that the physical state and chemical composition of the insulator must be of great importance in determining electrical phenomena.
Measurement of Capacity.-Numerous methods have been devised for the measurement of the electrical capacity of conductors in those cases in which it cannot be determined by calculation.
The electrical capacity of the whole earth considered as a sphere is about 800 microfarads.
Various special keys have been invented for performing the electrical operations expeditiously.
For the various precautions necessary in conducting the above tests special treatises on electrical testing must be consulted.
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.
A very powerful method of attacking problems in electrical distribution was first made known by Lord Kelvin in 1845 and is described as the method of electrical images.'
The point-charge -q at B is called the " electrical image " of the point-charge +q at A.
We find a precisely analogous effect in optics which justifies the term " electrical image."
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.
Hence this charge is the electrical image of the charge +q at A in the spherical surface.
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.
In the collected Scientific Papers of Lord Kelvin (3 vols., Cambridge, 1882), of James Clerk Maxwell (2 vols., Cambridge, 1890), and of Lord Rayleigh (4 vols., Cambridge, 1903), the advanced student will find the means for studying the historical development of electrical knowledge as it has been evolved from the minds of some of the master workers of the 19th century.
The general illuminant is electricity, and both electrical and gas services are owned by the municipality.
At present we are where we were in electrical science, when Newton produced curious sparks while rubbing glass with paper.
o% over the value of the factory products in 1900; among its manufactures are tobacco, cigars, chewing tobacco and snuff (value in 1905, $2,879,217), patent medicines (value in 1905, $2,133,198), flour and grist mill products ($1,089,910), men's clothing ($ 8 33, 8 35), and, of less importance, commercial and computing scales and time recorders, chemicals, distilled liquor, beer, fire-alarm apparatus, overalls, agricultural implements, wagons, electrical apparatus, refined oil, sheet metal, paper bags and envelopes, tacks and nails, window glass, glass-ware, clocks, whips and furniture (especially Morris chairs).
Its electrical conductivity is approximately 1.2, silver at 0° being taken as 100; it is the most diamagnetic substance known, and its thermoelectric properties render it especially valuable for the construction of thermopiles.
When present in other metals, even in very small quantity, bismuth renders them brittle and impairs their electrical conductivity.
Tin amalgam is used for "silvering" mirrors, gold and silver amalgam in gilding and silvering, cadmium and copper amalgam in dentistry, and an amalgam of zinc and tin for the rubbers of electrical machines; the zinc plates of electric batteries are amalgamated in order to reduce polarization.
It has iron-foundries, saw-mills, electrical works, and manufactures of bricks.
In art-work of this nature the principal points to be looked to in depositing are the electrical connexions to the cathode, the shape of the anode (to secure uniformity of deposition), the circulation of the electrolyte, and, in some cases, the means for escape of anode oxygen.
The electrical conductivity of sea-water increases with the salinity; at 59° F.
The two principal processes utilized in making calcium carbide by electrical power are the ingot process and the tapping process.
A third pencil traces an observation line in which a kick can be made at will by pressing any one of the electrical pushes placed about the car, and a fourth draws a datum line.
When chemical phenomena occur the molecule may be divided into atoms, and these atoms, in the presence of electrical phenomena, may themselves be further divided into electrons or corpuscles.
The results of this theory have placed the molecular conception of matter in an indisputable position, but even without this theory there is such an accumulation of electrical and optical evidence in favour of the molecular conception of matter that the tenability of this conception could not be regarded as open to question.
conjectured that thunder and lightning were electrical manifestations; in the same year he planned the lightning-rod (long known as " Franklin's rod "), which he described and recommended to the public in 1753, when the Copley medal of the Royal Society was awarded him for his discoveries.
The famous experiment with the kite, proving lightning an electrical phenomenon, was performed by Franklin in June 1752.
of quay walls, the wharfs being provided with electrical cranage.
Lesser interests, in the order of importance, with the product value of each in 1905, were: rubber goods ($53,133,020), tanned, curried and finished leather ($33,35 2, 999), in the manufacture of which Massachusetts ranked second among the states; paper and wood pulp' ($32,012,247), in the production of which the state ranked second among the states of the Union; slaughtering and meat packing ($30,253,838); printing and publishing ($33,900,7}8, of which $21,020,237 was the value of newspapers and periodicals); clothing ($21,724,056); electrical machinery, apparatus and supplies ($15,882,216); lumber ($12,636,329); iron and steel, steel works and rolling-mills products ($ 11, 947,73 1; less than in 1900); cordage and twine ($11,173,521), in the manufacture of which Massachusetts was second only to New York; furniture ($11,092,581); malt liquors ($11,080,944); jewelry ($10,073,595), Massachusetts ranking second to Rhode Island; confectionery ($9,317,996), in which Massachusetts was third among the states.
Nitric acid and lower nitrogen oxides are present, being formed by electrical discharges, and by the oxidation of atmospheric ammonia by ozone.
The striking discovery was, in 1903, made by the same investigators that the spontaneous luminosity of radium gives a spectrum of a kind never before obtained without the aid of powerful excitation, electrical or thermal.
OHMMETER, an electrical instrument employed for measuring insulation-resistance or other high electrical resistances.
Fleming, A Handbook for the Electrical Laboratory and Testing Room (2 vols., London, 1904); H.
Kempe, A Handbook of Electrical Testing (London, 1900); H.
Foundry and machine-shop products were valued at $115,876,193 in 1905, and electrical machinery, apparatus,.
Amphiaraus, foreseeing the disastrous issue of the war, at first refused to share in it; he had, however, promised Eriphyle when he married her that, in the event of any dispute arising between her brother and ' See " The Electrolysis of Copper Sulphate in Standardizing Electrical Instruments," by A.
It has manufactures of toys and agricultural machinery, electrical works and breweries.
Other products exceeding $1,000,000 in value were: leather ($14, 0 74,397), Milwaukee being second in the manufacture of leather among the cities of the United States; foundry and machine shop products ($10,232,723); iron and steel ($7,010,793); flour and grist-mill products ($6,320,428) slaughtering and meat-packing products ($5,95 8, 5 1 5); men's clothing ($4,759,54 8); boots and shoes ($2,929,405); electrical machinery, apparatus and supplies ($2,257,229); chewing and smoking tobacco ($1,966,930) and cigars and cigarettes ($1,540,019); furniture ($1,767,290); trunks and valises ($1,623,310); hosiery and knit goods ($ 1, 535, 1 7 6); confectionery ($1,379,668); stoves and furnaces ($1,288,931); leather gloves and mittens 41,207,633); structural iron work ($1,037,217); wooden packing boxes ($1,024,750); and paints ($ 1, 01 5,774).
Its largest industry is, perhaps, the manufacture of thread; there are also in the town ironworks, breweries, shipbuilding yards and electrical works.
Fleming, A Handbook for the Electrical Laboratory and Testing Room (London, 1904); T.
This description, quoted from James Clerk Maxwell's article in the 9th edition of the Encyclopaedia Britannica, represents the historical position of the subject up till about 1860, when Maxwell began those constructive speculations in electrical theory, based on the influence of the physical views of Faraday and Lord Kelvin, which have in their subsequent development largely transformed theoretical physics into the science of the aether.
But on the modern theory, which includes the play of electrical phenomena as a function of the aether, there are other considerations which show that this number io 2 is really an enormous overestimate; and it is not impossible that the co-efficient of ultimate inertia of the aether is greater than the co-efficient of inertia (of different kind) of any existing material substance.
It is, however, in complete accordance with a view that would make the aether near the earth fully partake in its orbital motion - a view which the null effect of convection on all terrestrial optical and electrical phenomena also strongly suggests.
When Clerk Maxwell pointed out the way to the common origin of optical and electrical phenomena, these equations naturally came to repose on an electric basis, the connexion having been first definitely exhibited by FitzGerald in 1878; and according as the independent variable was one or other of the vectors which represent electric force, magnetic force or electric polarity, they took the form appropriate to one or other of the elastic theories above mentioned.
It offers courses leading to the degrees of Bachelor of Arts and Bachelor of Science in civil engineering, in electrical engineering and in chemistry.
Having completed his education in Paris, he entered his father's business, but devoted his leisure hours to chemical and electrical researches, and between 1836 and 1848 published several papers on these subjects.
These figures are from the U.S. census, and are of course for Cincinnati proper: some of the largest industrial establishments, however, are just outside the city limits - among these are manufactories of soap (the Ivory Soap Works), machine tools, electrical machinery and appliances, structural and architectural iron work, and office furnishings.
Slabs are also manufactured, and, being readily cut, planed, dressed and enamelled, are used for chimney pieces, billiard tables, wall linings, cisterns, paving, tomb-stones, ridge rolls, electrical switch-boards and various other architectural and industrial purposes.
In 1871 he began to turn his attention to experimental physics, his earlier researches bearing upon the polarization of light and his later work upon the electrical discharge in rarefied gases.
The potentiometer and the divided resistance constitute a sort of electrical scaleyard by means of which any electromotive force or difference of potential can be compared with the electromotive force of a standard cell.
In electrical measurements connected with incandescent electric lamps the potentiometer is of great use, as it enables us to make accurately and nearly simultaneously two measurements, one of the current through the lamp and the other of the potential difference of the terminals.
Fleming, Handbook for the Electrical Laboratory and Testing Room, vol.
Aspinall Parr, Electrical Engineering Measuring Instruments (London, 1903); W.
and the thickness of a man's thigh, and frequents the marshes of Brazil and the Guianas, where it is regarded with terror, owing to the formidable electrical apparatus with which it is provided.
These fish are eaten by the Indians, who, before attempting to capture them, seek to exhaust their electrical power by driving horses into the ponds.
According to Lord Cockburn the effect of the first number of the Edinburgh Review was "electrical."
There are methods of measuring electrical power by means of electrostatic voltmeters, or of quadrant electrometers adapted for the purpose, which when so employed may be called electrostatic wattmeters.
Fleming, Handbook for the Electrical Laboratory and Testing Room (1903); Id., The Alternate Current Transformer in Theory and Practice (1905); G.
Aspinall Parr, Electrical Engineering Measuring Instruments (1903); A.
The pressure to which the Sheffield plate was submitted produces a definite colour and texture which is absent from the surface produced by the deposit of silver in a liquid medium by electrical means, and the coat of silver is spread by the latter uniformly over the whole surface without a break, while in the former the junction between the embossed ornaments and the silver strips covering the cut edges may often be detected on careful examination.
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.
On the southern border of the borough is Lake Bantam (about 900 acres, the largest lake in the state) whose falls, at its outlet, provide water power for factories of carriages and electrical appliances.
Fleming, Handbook for the Electrical Laboratory and Testing-Room (London, 1903); G.
Aspinall Parr, Electrical Engineering Measuring Instruments (London, 1903); K.
In 1905 its factory product was valued at $6,809,979, an increase of 32.5% since 1900; 57.6% was in boots and shoes, and the manufactures of combs and silverware, silversmithing products, cotton goods and electrical supplies are also important.
Electrical Engineering >>
The almost universal adoption of electrical traction in towns has not led to the abandonment of the breeding of horses to the extent that was at one time anticipated.
The great velocity of electrical transmission suggested the possibility of utilizing it for sending messages; and, after many experiments and the practical advice and business-like co-operation of William Fothergill Cooke (1806-1879), a patent for an electric telegraph was taken out in their joint names in 1837.
In 1835, in a paper on "The Prismatic Decomposition of Electrical Light," he proved that sparks from different metals give distinctive spectra, which afforded a ready means of discriminating between them.
But it is by his electrical work that Wheatstone is best remembered.
He devised the "A, B, C" telegraph instrument, the automatic transmitter, by which messages may be sent at the rate of 500 words a minute, printing telegraph receivers of various forms, electrical chronoscopes, and many forms of electrical recording apparatus, - amongst others two sets of registering meteorological instruments, of which the earlier, described in 1842, was afterwards developed by Father A.
The company possesses one of the finest electric stations in the world, and electrical apparatus for the working of train signals is in operation.
Hitherto we were entirely and still are generally confined to electrical excitation or to chemical action as in the case of flames.
The view that visible radiation must be excited by the impact of such an electron is therefore quite consistent with the view that there is no essential difference between the excitement due to chemical or electrical action and that resulting from a sufficient increase of temperature.
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.
It was found that during the successive electrical oscillations the metallic lines can be observed to stretch farther and farther away from the poles, thus giving a measure of the gradual diffusion of the metal.
He founded the Sidereal Messenger in 1846, was one of the first to adopt (in 1848) the electrical method of recording observations, and published besides other works, The Orbs of Heaven (1848, &c.), and Popular Astronomy (1860), both reissued at London in 1892.
M`Kendrick, of Glasgow, he investigated the physiological action of light, and examined the changes which take place in the electrical condition of the retina under its influence.
Fleming, of University College, London, in the investigation of the electrical behaviour of substances cooled to very low temperatures.
But Faraday's chemical work, however important in itself, was soon completely overshadowed by his electrical discoveries.
Henceforward, whatever other subjects might from time to time claim his attention, it was from among electrical phenomena that he selected those problems to which he applied the full force of his mind, and which he kept persistently in view, even when year after year his attempts to solve them had been baffled.
Henry Cavendish had before 1773 discovered that glass, wax, rosin and shellac have higher specific inductive capacities than air, and had actually determined the numerical ratios of these capacities, but this was unknown both to Faraday and to all other electricians of his time, since Cavendish's Electrical Researches remained unpublished till 1879.
The first period of Faraday's electrical discoveries lasted ten years.
whether, when they cannot decompose, any state of electrical tension is present.
Besides investigating other phenomena connected with a vacuum, he constructed an electrical machine which depended on the excitation of a rotating ball of sulphur; and he made successful researches in astronomy, predicting the periodicity of the return of comets.
The study of the structure of atoms has suggested a connexion of mass with electrical phenomena which implies its dependence on motion; but this is not inconsistent with the observed fact of its practical constancy, to a high degree of accuracy, for bodies composed of atoms.
Electrical and chemical effects afford similar examples.
In order to explain the electrical properties of a solution, for instance of potassium chloride, we are driven to believe that each molecule of the salt is dissociated into two parts, potassium and chlorine, each associated with an electric charge equal in amount but opposite in sign.
To explain the electrical properties of sulphuric acid in aqueous solution, the supposition of three ions, two of hydrogen and one of the chemical group S04, is necessary.
Now the velocities u and v of the opposite ions under unit potential gradient, and therefore U and V under unit force, are known from electrical data.
When the mixed gases were in the right proportion, the rate of absorption was about 3 o c.c. per hour, about: thirty times as fast as Cavendish could work with the electrical machine of his day.
The course of electrical events attending the operation of a Ruhmkorff coil being extremely complicated, special interest attaches to some experiments conducted by John Trowbridge and T.
About 1879 dynamos began to be introduced into metallurgical practice, and from that date onwards numerous schemes for utilizing this cheaper source of energy were brought before theublic. The first electrical method worthy lectrical P y reduction.
That this process did not depend upon electrolysis, but was simply an instance of electrical smelting or the decomposition of an oxide by means of carbon at the temperature of the electric arc, is shown by the fact that the Cowles furnace would work with an alternating current.
Its electrical conductivity, determined on 99.6% metal, is 60.5% that of copper for equal volumes, or double that of copper for equal weights, and when chemically pure it exhibits a somewhat higher relative efficiency.
With the increasing price of copper, it is coming into vogue as an electrical conductor for uncovered mains; it is found that an aluminium wire 0.126 in.
Bare aluminium strip has recently been tried for winding-coils in electrical machines, the oxide of the metal acting as insulators between the layers.
In the 18th century, and early in the 19th, Norwich had a lucrative trade with the Atlantic ports and the West Indies, but later manufacturing became the most important industry; the manufactures including textiles, cutlery, firearms, paper, electrical supplies, printing presses, &c. In 1905 the factory products were valued at $6,022,391.
ELECTRICAL (or [[Electrostatic) Machine]], a machine operating by manual or other power for transforming mechanical work into electric energy in the form of electrostatic charges of opposite sign delivered to separate conductors.
A primitive form of frictional electrical machine was constructed about 1663 by Otto von Guericke (1602-1686).
Edward Nairne's electrical machine (1787) consisted of a glass cylinder with two insulated conductors, called prime conductors, on glass legs placed near it.
- Ramsden's electrical machine.
He also devised an alternating current electrical machine in which the discharge balls were alternately positive and negative.
Gray, Electrical Influence Machines, their Development and Modern Forms (London, 1903).
Determinations of the electrical conductivity of the diazonium chloride and nitrate also show that the diazonium radical is strictly comparable with other quaternary ammonium ions.
On mixing dilute solutions of the diazonium hydroxide and the alkali together, it is found that the molecular conductivity of the mixture is much less than the sum of the two electrical conductivities of the solutions separately, from which it follows that a portion of the ions present have changed to the non-ionized condition.
It has also breweries, distilleries and electrical works.
It is famous for its manufacture of toys; its other industries are the making of glass and porcelain articles, electrical works and breweries.
The establishment of San Vito is devoted entirely to the production of artillery; that of San Bartolomeo is exclusively used for electrical works and the manufacture 'of submarine weapons, especially torpedoes.
Coal and iron ore abound in the vicinity, and the city, manufactures iron, steel, tin plate, electrical and telephone supplies, shovels, boilers, leather, flour, brick and tile, salt, furniture and several kinds of vehicles.
The town has railway, machine and electrical works; cloth, gloves and buttons are also manufactured here, and there are spinning-mills.
The electrical resistance is about that of ordinary glass, and is diminished by one-half during exposure by Rntgen rays; the dielectric constant (16) is greater than that which should correspond to the specific gravity.
The most important methods may be classified roughly under three heads - (I) Steady Flow, (2) Variable Flow, (3) Electrical.
The thermal capacity and electrical conductivity were measured at various temperatures on the same specimens of metal.
One important result, which might be regarded as established by this work, was that the ratio k/k of the thermal to the electrical conductivity, though nearly constant for the good conductors at any one temperature such as 0° C., increased with rise of temperature nearly in proportion to the absolute temperature.
are two electrical methods which have been recently applied to the measurement of the conductivity of metals, (a) the resistance method, devised by Callendar, and applied by him, and also by R.
In the electrical method, observations of the variable flow are useful for finding the value of c for the specimen, but are not otherwise required.
Moreover, the variation of thermal conductivity with temperature is small and uncertain, whereas the variation of electrical conductivity is large and can be accurately determined, and may therefore be legitimately utilized for eliminating the external heat-loss.
P. Chattock, employing an electrical method, deserves mention on account of the careful elimination of various errors (Phil.
The progress of technical studies and industrial enterprise enabled Germany to take a leading place in railway and shipbuilding,in the manufacture of military weapons, in chemical experiments, and in electrical work.
If, as is now generally believed, aurora represents some form of electrical discharge, it is only reasonable to suppose that the auroral lines arise from atmospheric gases.
All or nearly all the most recent regard it as some form of electrical discharge.
The chief varieties of this ware are vitrified china, belleek china, semi-porcelain, white granite and c. c. ware, vitrified porcelain for electrical supplies, porcelain bath tubs and tiles, and terra-cotta.
The town also contains distilleries, saw-mills, oil-mills, tanneries, breweries and electrical works.
The town is an important industrial centre, having tobacco and leather factories, electrical and other mechanical works, and breweries.
It can be demonstrated that they are practically indefatigable - repeatedly stimulated by electrical currents, even through many hours, they, unlike muscle, continue to respond with unimpaired reaction.
The college now grants the degrees of "Bachelor of Arts," "Cultural Bachelor of Science" and "Vocational Bachelor of Science"; the Department of Graduate Studies, the degrees of "Graduate in a School," "Master of Arts," "Master of Science" and "Doctor of Philosophy"; the Department of Law, the degree of "Bachelor of Laws"; the Department of Medicine, the degree of "Doctor of Medicine"; the Department of Engineering, the degrees of "Civil Engineer," "Mechanical Engineer," "Electrical Engineer," "Mining Engineer" and "Chemical Engineer"; and the Department of Agriculture, the degree of "Bachelor of Science in Agriculture."
On his return to London six years later he became professor of applied physics at the Finsbury College of the City and Guilds of London Technical Institute, and in 1884 he was chosen professor of electrical engineering at the Central Technical College, South Kensington.
He published, both alone and jointly with others, a large number of papers on physical, and in particular electrical, subjects, and his name was especially associated, together with that of Professor John Perry, with the invention of a long series of electrical measuring instruments.
In 1870 he became a fellow of the Chemical Society, and in 1872 graduated D.Sc. of London in electrical science.
Schonbein (loc. cit.) assumed that the ordinary oxygen molecule is decomposed into two parts which carry electrical charges of opposite kinds, the one with the positive charge being called "antozone" and the other carrying the negative charge being called "ozone," one variety being preferentially used up by the oxidizing compound or element and the other for the secondary reaction.
The greatest increase of products between 1890 and 1900 was in the manufacture of electrical apparatus (2400%), in which the increase in value of product was 37.2%.
cotton-spinning, dyeing, motor-manufacture (City & Guilds of London Institute), architecture (Royal Institute of British Architects), commercial subjects, shorthand (the Society of Arts and London Chamber of Commerce), engineering (Institutions of Civil Engineers, of Mechanical Engineers, and of Electrical Engineers).
The town has electrical works, but its industries are mainly concerned with the preparation of wine, the best kinds being Rudesheimer Berg, Hinterhaus and Rottland.
The two most important varieties of the method are (a) mechanical, and (b) electrical.
A more convenient unit of work or energy, in practice, on account of the smallness of the erg, is the joule, which is equal to 10.7 ergs, or one watt-second of electrical energy.
On account of its practical convenience, and its close relation to the international electrical units, the joule has been recommended by the British Association for adoption as the absolute unit of heat.
Expressed In J Oules Per Calorie The Result Is 4.1832, Which Agrees Very Closely With The Value Foand By Rowland As The Mean Over The Range 15° To 20° C. The Value 4.183 Is Independently Confirmed In A Remarkable Manner By The Results Of The Electrical Method Described Below, Which Give 4.185 Joules For The Mean Calorie, If Rowland'S Value Is Assumed As The Starting Point, And Taken To Be 4.180 Joules At 20° C.
The Value Of The International Electrical Units Has By This Time Been So Accurately Determined In Absolute Measure That They Afford A Very Good, Though Indirect, Method Of Determining The Mechanical Equivalent Of Heat.
But, Quite Apart From This, Electrical Methods Possess The Greatest Value For Calorimetry, On Account Of The Facility And Accuracy Of Regulating And Measuring The Quantity Of Heat Supplied By An Electric Current.
The Defects Of The Earlier Work From An Electrical Point Of View Lay Chiefly In The Difficulty Of Measuring The Current With Sufficient Accuracy Owing To The Imperfect Development Of The Science Of Electrical Measurement.
These Difficulties Have Been Removed By The Great Advances Since 1880, And In Particular By The Introduction Of Accurate Standard Cells For Measurements Of Electrical Pressure.
Assoc. Reports, 1897 And 1899) Adopted An Entirely Different Method Of Calorimetry, As Well As A Different Method Of Electrical Measurement.
The Absolute Value Of The Specific Heat Deduced Necessarily Depends On The Absolute Values Of The Electrical Standards Employed In The Investigation.
It Must Be Admitted That It Is Desirable To Redetermine The Variation Of The Specific Heat Above 100° C. This Is Very Difficult On Account Of The Steam Pressure, And Could Not Easily Be Accomplished By The Electrical Method.
(3) The Absolute Or Mechanical Unit, The Quantity Of Heat Equivalent To A Given Quantity Of Mechanical Or Electrical Energy.
The Electrical Resistance Thermometer Of Platinum Presents Very Great Advantages For This Purpose Over The Mercury Thermometer In Point Of Reproducibility, Accuracy And Adaptability To The Practical Conditions Of Experiment.
The Natural Point To Select Would Be That Of Minimum Specific Heat, But If This Occurs At 40° C. It Would Be Inconveniently High For Practical Realization Except By The Continuous Electrical Method.
Nickel is used for the manufacture of domestic utensils, for crucibles, coinage, plating, and for the preparation of various alloys, such as German silver, nickel steels such as invar (nickel, 35.7%; steel, 64.3%), which has a negligible coefficient of thermal expansion, and constantan (nickel, 45%; copper, 55%), which has a negligible thermal coefficient of its electrical resistance.
In May 1755 he was elected a fellow of the Royal Society of London, and published several papers on electrical subjects in the Phil.
Beccaria did much, in the way both of experiment and exposition, to spread a knowledge of the electrical researches of Franklin and others.
LEYDEN JAR, or Condenser, an electrical appliance consisting in one form of a thin glass jar partly coated inside and outside with tin foil, or in another of a number of glass plates similarly coated.
The university was chartered in 1866; it embraces a school of technology, with courses in civil, mechanical, metallurgical, mining, electrical and chemical engineering, electrometallurgy and chemistry, and a school of general literature (1878), with classical and Latin-scientific courses.
The principal buildings of the university are Packer Hall (1869), largely taken up by the department of civil engineering, the chemical and metallurgical laboratory, the physical and electrical engineering laboratory, the steam engineering laboratory, Williams Hall for mechanical engineering, &c., Saucon Hall for the English department, Christmas Hall, with drawing-rooms and the offices of the Y.M.C.A., the Sayre astronomical observatory, the Packer Memorial Church, the university library (1897), dormitories (1907) given by Andrew Carnegie, Drown Memorial Hall, a students' club, the college commons, and a gymnasium.
over the sill at high water of spring tides; the construction of new jetties at the entrance to the tidal basin and at the north wall; the establishment of a coal wharf with hydraulic appliances; a torpedo range in the harbour; the erection of various buildings such as torpedo and gun-mounting stores, electrical shops and numerous subsidiary works; and extensive dredging of the harbour to increase the berthing accommodation for the fleet.
The college offers four-year courses in agronomy, animal husbandry, dairying, domestic economy, general science, veterinary medicine, and civil, mechanical, electrical and mining engineering.
Volta made here his first electrical experiments.
Pavia has a number of iron-foundries, military engineering and electrical production works, and other factories, as well as a large covered market, built in 1882.
the house of the committee (1890), banks, a theatre, a circus, a new semicircular canal and a second floating bridge, underground galleries, a water-supply, an electrical tramway, temperance tea-shops and restaurants kept by the Society of Tradesmen.
it must be such that the leaves will remain for hours or days in a state of steady divergence when an electrical charge has been given to them.
While resident in Italy for his health from 1845 to 1847, he occupied himself with researches on the electrical organ of the torpedo and on nervous organization generally; these he published in1853-1854(Neurologische Untersuchungen, Gottingen), and therewith his physiological period may be said to end.
Electrical studies seem next to have engaged his attention, and in 1771 and 1772 he read to the Royal Society his "Attempt to explain some of the principal phenomena of electricity by an elastic fluid," which was followed in 1775 by an "Attempt to imitate the effects of the Torpedo (a fish allied to the ray)" (Phil.
But these two memoirs contain only a part of the electrical researches he carried out between 1771 and 1781, and many more were found after his death in a number of sealed packets of papers.
The contents of these for a long time remained unknown, but ultimately by permission of the duke of Devonshire, to whom they belonged, they were edited by James Clerk Maxwell and published in 1879 by the Cambridge University Press as the Electrical Researches of the Hon.
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.
He was president of the Institution of Electrical Engineers (then the Society of Telegraph Engineers) in 1877.
This article is devoted to a general sketch of the history of the development of electrical knowledge on both the theoretical and the practical sides.
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.
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.
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.
The principles of telegraphy (land, submarine and wireless) and of telephony are discussed in the articles Telegraph and Telephone, and various electrical instruments are treated in separate articles such as Amperemeter; Electrometer; Galvanometer; Voltmeter; Wheatstone'S Bridge; Potentiometer; Meter, Electric; Electrophorus; Leyden Jar; &C.
Hence the phenomena came to be collectively called electrical, a term first used by William Barlowe, archdeacon of Salisbury, in 1618, and the study of them, electrical science.
Gilbert was the first to conduct systematic scientific experiments on electrical phenomena.
The third covers the period between 1831 and Clerk Maxwell's enunciation of the electromagnetic theory of light in 1865 and the invention of the self-exciting dynamo, which marks another great epoch in the development of the subject; and the fourth comprises the modern development of electric theory and of absolute quantitative measurements, and above all, of the applications of this knowledge in electrical engineering.
We shall sketch briefly the historical progress during these various stages, and also the growth of electrical theories of electricity during that time.
An account of his electrical discoveries is given in the De magnete, lib.
electrical needle and proved that innumerable bodies he called electrica, when rubbed, can attract the needle of the versorium (see Electroscope).
Otto von Guericke (1602-1686) constructed the first electrical machine with a revolving ball of sulphur (see Electrical Machine), and noticed that light objects were repelled after being attracted by excited electrics.
Sir Isaac Newton substituted a ball of glass for sulphur in the electrical machine and made other not unimportant additions to electrical knowledge.
about 1707, the results of his electrical inquiries.
Various improvements were made in the electrical machine, and thereby experimentalists were provided with the means of generating strong electrification; C. F.
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.
Benjamin Franklin (1706-1790) was one of the great pioneers of electrical science, and made the evermemorable experimental identification of lightning and electric spark.
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.
A cloud passed without any electrical indications, and he began to despair of success.
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.
Canton first suggested the use of an amalgam of mercury and tin for use with glass cylinder electrical machines to improve their action.
We shall make mention lower down of Canton's contributions to electrical theory.
Ebenezer Kinnersley (1711-1778) of Philadelphia made useful observations on the elongation and fusion of iron wires by electrical discharges (Phil.
He also made many experiments with the tourmaline when cut into thin slices, and reduced to the finest powder, in which state each particle preserved its pyro-electricity; and he showed that scolezite and mesolite, even when deprived of their water of crystallization and reduced to powder, retain their property of becoming electrical by heat.
Bancroft was the first person who distinctly suspected that the effects of the torpedo were electrical.
1795) and Jan Ingenhousz (1730-1799) proved by many curious experiments that the shock of the torpedo was an electrical one (Phil.
1 773, 1 775) examined and described the anatomical structure of its electrical organs.
The work of Henry Cavendish (1731-1810) entitles him to a high place in the list of electrical investigators.
Amongst Cavendish's important contributions were his exact measurements of electrical capacity.
In connexion with this subject he anticipated one of Faraday's The Electrical Researches of the Hon.
He seems in this way to have educated in himself a very precise " electrical sense," making use of his own nervous system as a kind of physiological galvanometer.
Accordingly the close of the 18th century drew into the arena of electrical investigation on its mathematical side P. S.
See Cavendish's Electrical Researches,.
- We now enter upon the second period of electrical research inaugurated by the epoch-making discovery of Alessandro Volta (1745-1827).
Galvani had made in 1790 his historic observations on the muscular contraction produced in the bodies of recently killed frogs when an electrical machine was being worked in the same room, and described them in 1791 (De viribus electricitatis in motu musculari commentarius, Bologna, 1791).
Volta maintained that the mere contact of metals was sufficient to produce the electrical difference of the end plates of the pile.
Ohm (1787-1854) rendered a great service to electrical science by his mathematical investigation of the voltaic circuit, and publication of his paper, Die galvanische Kette mathematisch bearbeitet.
- With this supremely important discovery of Faraday's we enter upon'the third period of electrical research, in which that philosopher himself was the leading figure.
He not only collected the facts concerning electromagnetic induction so industriously that nothing of importance remained for future discovery, and embraced them all in one law of exquisite simplicity, but he introduced his famous conception of lines of force which changed entirely the mode of regarding electrical phenomena.
Space compels us to limit our account of the scientific work done by Faraday in the succeeding twenty years, in elucidating electrical phenomena and adding to the knowledge thereon, to the very briefest mention.
Faraday's ideas thus pressed upon electricians the necessity for the quantitative measurement of electrical phenomena.'
Weber at the same time deduced the mathematical laws of induction from his elementary law of electrical action, and with his improved instruments arrived at accurate verifications of the law of induction which by this time had been developed mathematically by Neumann and himself.
- About 1842 Lord Kelvin (then William Thomson) began that long career of theoretical and practical discovery and invention in electrical science which revolutionized every department of pure and applied electricity.
By his studies in electrostatics, his elegant method of electrical images, his development of the theory of potential and application of the principle of conservation of energy, as well as by his inventions in connexion with electrometry, he laid the foundations of our modern knowledge of electrostatics.
From 1842 onwards to the end of the 19th century, he was one of the great master workers in the field of electrical discovery and research.
2 The quantitative study of electrical phenomena has been enormously assisted by the establishment of the absolute system of electrical measurement due originally to Gauss and Weber.
The British Association for the advancement of science appointed in 1861 a committee on electrical units, which made its first report in 1862 and has existed ever since.
Hence although Maxwell's theory of electrical action when first propounded found many adherents in Great Britain, it did not so much dominate opinion on the continent of Europe.
-With the publication of Clerk Maxwell's treatise in 1873, we enter fully upon the fourth and modern period of electrical research.
Gramme (1826-1901) inaugurated a departure from which we may date modern electrical engineering.
Stearn in England, succeeded in completely solving the practical problems. From and after that date incandescent electric lighting became commercially possible, and was brought to public notice chiefly by an electrical exhibition held at the Crystal Palace, near London, in 1882.
Going back a few years we find the technical applications of electrical invention had developed themselves in other directions.
Polyphase alternators were first exhibited at the Frankfort electrical exhibition in 1891, developed as a consequence of scientific researches by Galileo Ferraris (1847-1897),Nikola Tesla,M.
Thus in twenty years from the invention of the Gramme dynamo, electrical engineering had developed from small beginnings into a vast industry.
Long distance electrical transmission had been before that time exemplified in the great scheme of utilizing the falls of Niagara.
This theory was founded on the following principles: - (I) the particles of the electric fluid repel each other with a force decreasing as the distance increases; (2) the particles of the electric fluid attract the atoms of all bodies and are attracted by them with a force obeying the same law; (3) the electric fluid exists in the pores of all bodies, and while it moves without any obstruction in conductors such as metals, water, &c., it moves with extreme difficulty in so-called non-conductors such as glass, resin, &c.; (4) electrical phenomena are produced either by the transference of the electric fluid of a body containing more to one containing less, or from its attraction and repulsion when no transference takes place.
In the elucidation of electrical phenomena, however, towards the end of the 18th century, a modification of the two-fluid theory seems to have been generally preferred.
The formulation of electrical theory as far as regards operations in space free from matter was immensely assisted by Maxwell's mathematical theory.
Oliver Heaviside after 1880 rendered much assistance by reducing Maxwell's mathematical analysis to more compact form and by introducing greater precision into terminology (see his Electrical Papers, 1892).
This is perhaps the place to refer also to the great services of Lord Rayleigh to electrical science.
Succeeding Maxwell as Cavendish professor of physics at Cambridge in 1880, he soon devoted himself especially to the exact redetermination of the practical electrical units in absolute measure.
He followed up the early work of the British Association Committee on electrical units by a fresh determination of the ohm in absolute measure, and in conjunction with other work on the electrochemical equivalent of silver and the absolute electromotive force of the Clark cell may be said to have placed exact electrical measurement on a new basis.
He also made great additions to the theory of alternating electric currents, and provided fresh appliances for other electrical measurements (see his Collected Scientific Papers, Cambridge, 1900) .
Electric Waves.-In the decade 1880-1890, the most important advance in electrical physics was, however, that which originated with the astonishing researches of Heinrich Rudolf Hertz (1857-1894).
Such an arrangement constitutes in effect a condenser, and when the two plates respectively are connected to the secondary terminals of an induction coil in operation, the plates are rapidly and alternately charged, and discharged across the spark gap with electrical oscillations (see Electrokinetics).
The sum total of all these contributions to electrical knowledge had the effect of establishing Maxwell's principles on a firm basis, but they also led to technical inventions of the very greatest utility.
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.
Thomson's " Report on Electrical Theories " (Brit.
Assoc. Report, 1885), in which he divides electrical theories enunciated during the 10th century into four classes, and summarizes the opinions and theories of A.
The electrical pressure required to force a current of this intensity through the solution, and to overcome a certain opposing electromotive force arising from the more electro-negative impurities of the anode, depends upon the composition of the bath and of the anodes, the distance between the electrodes, and the temperature, but under the usual working conditions averages o-3 volt for every pair of electrodes in series.
With too% currentefficiency and a potential difference of 0.3 volt between the electrodes, t lb of copper should require about o-154 electrical horse-power hours as the amount of energy to be expended in the tank for its production.
He studied the phenomena of electrical oscillations from 1869 to 1871, and in the latter year he announced that the velocity of the propagation of electromagnetic induction was about 314,000 metres per second.
Faraday had shown that the passage of electrical action involved time, and he also asserted that electrical phenomena are brought about by changes in intervening non-conductors or dielectric substances.
This led Clerk Maxwell to frame his theory of electro-dynamics, in which electrical impulses were assumed to be transmitted through the ether by waves.
Since the electrical repulsion of the balls is equal to C 2V2 4 12 sin 2 0 dynes, where C = r is the capacity of either ball, and this force is balanced by the restoring force due to their weight, Wg dynes, where g is the acceleration of gravity, it is easy to show that we have _ 21sin 0 r " tan V 8 r as an expression for their common potential V, provided that the balls are small and their distance sufficiently great not sensibly to disturb the uniformity of electric charge upon them.
The most important improvements in connexion with electrometers are due, however, to Lord Kelvin, who introduced the guard plate and used gravity or the torsion of a wire as a means for evaluating the electrical forces.
When turbines, as often happens in land practice, are directly coupled to electrical generators, their horse-power can be deduced from the electrical output.
Two points are selected on the surface of the shaft at different positions along it, and the relative displacement which occurs between them round the shaft when power is being transmitted is determined either by electrical means, as in the Denny-Johnson torsion-meter, or optically, as in the Hopkinson-Thring and Bevis-Gibson instruments.
Besides shipbuilding its other industries are matchmaking, silk-weaving, hair-working, copper-working, tubemaking, weaving, and the manufacture of locomotives and electrical apparatus.
above the river level, and has wide, well-paved streets shaded by oaks and elms. It is 659 the seat of the Indiana State Normal School (1870), which had in 1909 a library of about 50,000 volumes, 52 instructors and an average term enrolment of 988 students, and of the Rose Polytechnic Institute, which was founded in 1874 by Chauncey Rose (1794-1877), was opened in 1883, offers courses in mechanical, electrical, civil and chemical engineering and in architecture, and in 1909 had 22 instructors and 214 students.
Electrical wind storms are frequent in these high altitudes.
Among its industrial establishments are rolling mills, tube and pipe works, furnaces, steel mills, a brass foundry, and manufactories of electrical railway supplies, boxes, asbestos coverings, enamel work and ice.
When a feebly electrified body (such as a stick of sealing-wax gently rubbed upon the coat sleeve) is brought into its neighbourhood, the jet undergoes a remarkable transformation and appears to become coherent; but under more powerful electrical action the scattering becomes even greater than at first.
Under moderate electrical influence there is no material change in the resolution into drops, nor in the subsequent motion of the drops up to the moment of collision.
When the electrical influence is more powerful, the repulsion between the drops is sufficient to prevent actual contact, and then, of course, there is no opportunity for amalgamation.
In this condition there is complete electrical insulation between the jets, as may be proved by the inclusion in the circuit of a delicate galvanometer, and a low electro-motive force.
It would seem that the forces of electrical attraction act with peculiar advantage.
Extremely local contacts of the liquids, while opposed by capillary tension which tends to keep the surfaces flat, are thus favoured by the electrical forces, which moreover at the small distances in question act with exaggerated power.
The effect upon Berlin of the successful issue of the FrancoPrussian War of 1870-71 was electrical.
There he began his lectures on electrical science which brought him invitations to lecture all over the United Kingdom and made him a power in both the scientific and industrial worlds.
This work, which embodied the results of many years' research, was distinguished by its strict adherence to the scientific method of investigation by experiment, and by the originality of its matter, containing, as it does, an account of the author's experiments on magnets and magnetical bodies and on electrical attractions, and also his great conception that the earth is nothing but a large magnet, and that it is this which explains, not only the direction of the magnetic needle north and south, but also the variation and dipping or inclination of the needle.
The rifle factory, founded in 1830 by Josef Werndl, is the largest in Austria, and since 1882 it has added the manufacture of bicycles and electrical plant.
In 1838 he made important investigations in regard to the conditions and range of induction from electrical currents - showing that induced currents, although merely momentary, produce still other or tertiary currents, and thus on through successive orders of induction, with alternating signs, and with reversed initial and terminal signs.
Among many minor observations, he discovered in 1842 the oscillatory nature of the electrical discharge, magnetizing about a thousand needles in the course of his experiments (Proc. Am.
He traced the influence of induction to surprising distances, magnetizing needles in the lower story of a house through several intervening floors by means of electrical discharges in the upper story, and also by the secondary current in a wire 220 ft.
Practical results with a large plant indicate an expenditure of 1.23 electrical horse-power hours per 100 oz.
In 1821 he was busy with electrical experiments and in 1822 with investigations of the fluids contained in the cavities of crystals in rocks.
In the same year the admiralty consulted the Royal Society as to a means of preserving the copper sheathing of ships from corrosion and keeping it smooth, and he suggested that the copper would be preser