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adorned tombs of Luther and Melancthon in the of a celebrated author's works. Here also is centre of the old Castle Church at Wittenberg shown the armior and other relics of Grand Duke are visited by thousands, who scarcely deign to Bernard, one of the Protestant leaders in the look at the stately statues of the electors John “ Thirty Years War," who died in 1639, and was and Frederick in the front part of the same buried in this city church. Thus have the rulers church. Such is the way of the world; it suffers of Saxe-Weimar remembered and honored the factitious notoriety and high rank to pass into men who have contributed to the greatness of oblivion, but persists in expressing its admiration their realms. Charles Augustus was the Mæcenas for genius.

of German literature. He made little Weimar On our return from the cemetery, we pass by “the Athens of Germany," and the parks that to the colossal bronze statue of Wieland, the author this day add so much to the picturesqueness of the of “Agathan and Oberon," and the first translator city have been to Germany what the groves of of Shakspeare into German. Herder is another the Academy were to Greece. great name in Weimar. His house, the parsonage The park extends along the charming banks of of the city church, is unknown to tourists as the the Ilm, containing trees and shrubbery, fountains place where “lived, labored, and died Johann gushing forth from the living rock; Denkmels, or Gottfried Von Herder,'' according to the inscrip rude stone monuments; bowers and summer resition on the front tablet. The church is a large dences, and the beautiful Romishe Haus, built in building with a quaint roof, and a spire on each the form of a Grecian temple, standing in the end, erected in 1400. Herder rests in the nave midst of a grove where Goethe used to spend the of the church, and his statue stands directly in warm season. A botanical garden adorns the front, with a scroll in his hand, on which is centre of the park, and a fine old avenue of trees inscribed the German words, Licht, Lieben, | connects it with the palace-like chateau of BelLeben"—Light, Love, Life. This church con vedere. The .ducal library is a fortress-looking tains some of the finest paintings by Cranach. building with a quaint old tower of the mediæval

The grand ducal palace, erected under Goethe's style on one end, and contains nearly one hundred superintendence, contains some good frescoes. and fifty thousand books and MSS., and busts and There are four rooms named from these four portraits of distinguished men who have resided literary characters: Schiller's, containing illus- at Weimar. It also contains some interesting trations from “Wallenstein,” “Marie Stuart," etc.; relics, the gown worn by Luther when a monk, Goethe's, illustrations from “Egmont,” “Faust," Goethe's Court uniform, the belt of Gustavus etc.; Wieland's, scenes from the “ Oberon ;" Adolphus, and other curiosities pertaining to litHerder's, adorned with symbolical characters of his erature and history. The most brilliant period of different professions. The whole is remarkably rich Weimar's history seems to be opened to view here. and suggestive, like the best illustrative engravings | It is veritably a school of genius and lofty valor.

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ELECTRICITY—THE FORCE OF THE FUTURE.

By John A. Bower.

What is electricity? This is a question which near it to serve as a rubber. From this the has always perplexed us and perplexes us still. delighted philosopher obtained not only flashes This perplexity is, however, of little consequence, of light, but the snapping of the electric spark. for we have of late years made enormous strides To this philosopher is accredited the discovery of in the application of this subtle force. We are electrical repulsion. now getting a fair acquaintance with electricity, He observed that when a feather or any light and this acquaintance is giving us lessons as to substance was electrified and detached from the the sources from which it can best be obtained, surface of the body from which it was charged, it and how it can be employed.

would not again go near that body, but was driven We read of the old philosopher Thales rubbing away. Upon these experiments of attraction and a piece of yellow amber on his rough baize gar- repulsion, Otto Guericke endeavored to explain ment, and then picking up with it bits of down the motion of the moon around the earth, and and floating feathers. This experiment of the old it was not till the discoveries of Sir Isaac NewGreek philosopher, dated 600 years before Christ, ton were made known that this notion was d sseems to have no connection whatever with the pelled. elaborate plans now adopted for developing electricity that gives us light of such intensity as to compare with the sun for brilliancy, and heat so intense that it can even volatize refractory carbon. In both cases, however, the force is the same, the difference is in the intensity. Thales not only rubbed the amber and lifted up light substances by its influence, but he endeavored to explain the cause. He said the amber held a soul or essence which was awakened by friction, and went forth from the body in which it had previously lain dormant, and brought back the small particles by the invisible effluvium which it emitted. This

FIG. 1.—THE GALVANIC BATTERY. was the first hint given to the world of this subtle force which resides in everything and is as uni. Thus little by little more became known. Exversal as gravitation itself; and from this sub- periments also proved that certain substances constance, amber-electron-the name electricity it- ducted electricity freely and others did not; and self is derived. •

that those substances which gave out electricity We have after this no more direct notice of freely when excited were the very worst conductthis force till the beginning of the seventeenth ors, and vice versa. century, when Dr. Gilbert announced to the world Next came the discovery of the Leyden jar, by a list of about twenty substances, which he rubbed, which it was found that electricity could be stored and with them attracted not only light floating up; and a number of Leyden jars were arranged bodies, “but all solid matters whatever, including in a series, and thus a battery was formed. With metals, water, and oil.”

batteries of this description Franklin is said to We next hear of Mr. Boyle and Otto Guericke have succeeded in magnetizing steel needles. making experiments, and to the former is accred- This is the first notice of the connection between ited the first seeing of the electric light, while magnetism and electricity. Among other exthe latter was the first to make an electric machine. periments, he drew electricity from the clouds This machine consisted of a sulphur ball which by means of a kite, and proved it to be idenwas turned on an axis, and the hand was pressed tical with that obtained by an ordinary machine.

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A new phase was given to the science when, at mechanical force developing electricity is to take the end of the eighteenth century, the discoveries two plates of metal, one of copper, another of zine; of Galvani and Volta led to another method of having attached an insulating handle, join to each setting free electricity, by the combination called plate a wire connected with a delicate galvanthe galvanic battery. In all such battery arrange ometer; on gently striking the plates together, a ments electricity is set free by chemical force, i, e. current of electricity is detected by the deflection by two metals of an opposite character, one of of the needle, and a similar current is produced which readily dissolves in the acid liquid used in on separating them, but the needle will move in charging. A simple cell of such an arrangement the opposite direction. The mere act of stirring we show in Fig. 1.

up a little milk as it is boiling is sufficient to set How, then, is electricity produced ? In many free electricity, and even the smallest mechanical ways. If we take the ordinary plate or cylinder action can, under proper control, be shown to machine, mechanical energy must be employed to produce electricity.

Again, on the other hand, electric action can be changed into mechanical energy or heating energy; and chemical energy can be changed into heat, force, and electric energy.

Take, for example, a current of electricity from a battery: this can be carried by a wire, which must be covered with some insulating substance, several times round a piece of soft iron, as in Fig. 2; the iron at once becomes a magnet. It at once,

if free to move, arranges itself north and south, FIG. 2.—THE ELECTRO-MAGNET..

and acts in every way like a permanent magnet.

Here the chemical force from the battery is work the machine; this energy is changed into changed into magnetic force, which travels along electric energy; in the battery, chemical action of the wire. In fact, the wire itself acquires magnetic acid on the zinc, i.e. chemical energy, is changed powers, and magnetism is only another form of into electrical energy.

electricity. If we take a helix of wire by itself, as We cannot create force, any more than we can in Fig. 3, and send through it a current from the create matter. A force of one kind' can only battery, the wire becomes strongly magnetized, be gained at the expense of another kind of force. which may readily be tested. If the N end of a Take an ordinary case of rubbing two bits of wood permanent magnet be presented to the N end of together : they become heated; the mechanical the coil, repulsion at once takes place, but if the work of friction is thus changed into heat. In Send be presented attraction is the result. The the case of rubbing a piece of amber, sealing-wax, wire will also be found to have risen in temperaor ebonire with flannel, muscular force is used, ture. A part, therefore, of the chemical force is and the force is transformed into electric force, changed into electrical and a part into heat force. that gives to the amber, sealing-wax, or ebonite A bar of iron magnetized from a battery is the power of lifting bits of paper, pith-balls, or called an electro-magnet. The difference between any light substances. When the force is dissi- a piece of iron that is not magnetized and a magpated, another supply of mechanical energy is net is that the former attracts both poles alike, necessary to excite the electrical; and we must but, in magnets, like poles repel and unlike poles bear this in mind, that any force generated will attract. give out exactly as much energy as is given to it; Several discoveries of the late Sir Humphry but a good deal goes off as heat.

Davy were due to the chemical work which he In the ordinary electric machine the electric was able to get out of the first really large battery energy produced is entirely developed from me. that was made. This was at the Royal Institution chanical work; but not all the mechanical work is of Great Britain, where he put together as many changed into electricity, for a part of it is dissi- as two thousand cells of copper and zinc couples. pated in heat. A very pretty illustration of With a current from this enormous arrangement, potassium and sodium were first separated in their machines which are now giving us the electric elementary form from the salts containing them. light at a comparatively small cost. A brief With this same arrangement which gave such good description of the earliest and simplest of these chemical results, Sir Humphry Davy first produced machines must suffice for our purpose; the later the heating effect on two charcoal points at the and more complicated forms are only more comends of wires leading from the battery, so as to plete developments of the same principles. get a very brilliant electric light. This was the A very simple experiment will suffice to show first electric light of any intensity that had ever even the most uninitiated what is meant by an been witnessed. In this case zinc was being dis- induced current. If a small permanent magnet solved in the battery by the acid, thus setting free be held near to a piece of soft iron, the piece of chemical force and heat force of very great inten- | | iron becomes a magnet, and will hold up small sity. The zinc, in fact, was the fuel employed for pieces of iron or iron filings; on removing the supplying the energy.

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iron from the influence of the magnet, the force Still later, M. Gassiott made a much larger disappears, and the pieces of iron no longer cling battery, consisting of nine thousand couples; but to it. The same effect is produced if a bar magthis has been eclipsed by an immensely larger and net is placed in a coil of wire, also if one coil be more powerful arrangement by Dr. Warren De la inserted within another coil. This was the disRue. This is the largest battery, we believe, that covery of Faraday in 1831, and it was very quickly has ever been made, and consists of the enormous applied in the construction of the various magnetonumber of fourteen thousand six hundred cells, electric machines. The first was made by causing and its results are as magnificent as the proportions a magnet to revolve close to a double coil of wire, of the battery itself.

and this developed in the coil powerful currents Electric force developed in this form from bat- of electricity. The next most successful arrangeteries at the expense of zinc is too costly for ment was that which fixed the battery of permageneral employment as a mechanical or lighting nent magnets and made a double coil of wire to agent. The electricity employed for all working revolve close to and opposite the poles of the purposes is more cheaply derived from the combustion of coal, and the battery, for these purposes, has been discarded.

The steam-engine has become our great producer of electric force, and the one object of inventors now is to get out of the engine the utmost electric energy at the least possible cost.

Combined with the steam-engine, we must mention the discovery of the late Dr. Faraday, the discoverer of electro-magnetism, who first contrived a very ingenious machine for showing that not only will a magnet revolve round a wire, carrying a battery current of electricity, but that such a conducting-wire itself will revolve round a magnet. The powerful magneto-dynamic machines

FIG. 3.-A HELIX OF WIRE. that are now used to produce powerful electric currents are the results of the labors of this magnet, before which they are rotated with great earnest philosopher. Another important discovery speed by an endless band carried round the cirdue to Faraday is, that electric currents can be cumference of the axis and of the large wheel. induced or given to wires, or cores of iron, with- This is known as Clarke's machine, and is shown out their being in actual contact with the sources in Fig. 4. Here again the mechanical energy of of electricity. The skillful combinations of these turning the handle which rotates the double coil principles have been applied in the construction is changed into electric energy, and the more of the Gramme, the Siemens, the Brush, the rapid the rotation, the greater the amount of Bürgin, and the various other magneto-motor electricity set free.

VOL. XVII.—26

Just one word of explanation as to how the horizontal position to the other, then it is reversed, electric currents are formed.

and so on during every half rotation. The cores of the electro-magnets are fixed to an In this simple machine we have the secret of all iron plate, so that they really form an electro- the elaborate electro-motors now used for lighting magnet of the horse-shoe form. By magnetic re- purposes. The permanent magnets are, however, pulsion the N end is always opposite the S end frequently replaced by electro-magnets; or, if perof the permanent magnets, and the magnetic in- manent magnets are employed, they are generally tensity is greatest when the electro-magnet is hori. very weak, for the rapid rotation of the electrozontal, as in Fig. 4; but in the course of its ro- magnet is found to react on the other so that each tation it is as often vertical as horizontal, then the is immensely strengthened. The magnets are comcurrent is weakest. Then at every half revolution bined in series so as to produce the greatest effect, it will be horizontal, but its magnetismi will be re- and the rotation of the armatures in many cases versed, for the coil being reversed, iis poles must reaches as many as eight hundred revolutions per necessarily be changed. These rotations are, how minute. A small machine of this kind will drive

a lathe or work a saw; a large one will give a powerful light, or do such heavy mechanical work as driving looms, turning larger lathes or heavier

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saws.

As we have referred to both the galvanic battery and the steam-engine as our source of energy for working these machines, we may note this difference. In burning coal a large portion of its energy is dissipated in heat, whereas when a battery is employed nearly eight-ninths of its work is converted into electric energy. One pound of cual, however, will do as much work in a steam-engine in driving a dynamo machine as nine pounds of zinc burnt in a battery; and thirty pounds of coal cost the same as one pound of zinc, which is considerably in favor of coal. We have also several engines well adapted for the purpose of driving dynamo machines, worked entirely by gas. In many respects these gas engines are preferable to the furnace engines in which coal is used, for they are cleaner, and are always ready for work. Falling water may also be employed for developing electric energy. This is not merely an idea, but

has been worked out, in fact ; for Sir William FIG. 4.--CLARKE'S MACHINE.

Armstrong, at Craigside, near New Castle, is now

using the water from a running brook to work a ever, so rapid, and the change of polarity equally turbine which produces a force equal to that of a rapid, that the effect is apparently to produce a four-horse-power engine, so, as he says, “lhe continuous current. This current is conveyed brook lights his house." It has been said that along wires, and can be used for lighting, heating, the Falls of Niagara conld develop enough elecor chemical work, as may be required. The wires tricity to light the whole city of New York, and are connected with metallic springs that press con that the electric current for such a purpose could tinually on the axis of the electro-magnet, which be brought to that city by means of a small wire. axis is cut in two, and a piece of bone or box- In our sketch we have supposed that the falls are wood inserted, to insulate one-half from the other. not only able to light the city of New York, but The current circulates in one direction only as that the electric motors, worked by large turbines, long as the electro-magnet is passing from one with water diverted from the Falls, could work

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