K^GDOM.]

AND SURGICAL INSTRUMENTS.

North, North Central, and South Central Galleries.

457

v ^ectric. telegraph instrument, for the purpose of con-t ? ln S,general intelligence over the country,specimens of insulated wire, for submarine electric tele-; specimens taken from the English Channel , usedthe electric telegraph between Dover and Cape Grinez,nea t Calais.

^28 Henley, William Thomas, 46 St. John’s Street Road,Clerhemcell —Inventor and Manufacturer.

Large permanent horse-shoe magnet, weighing Gj cwt.latent electric telegraphs, worked by the magneto-le ctric current.

Fig. 1.

Fig. 3.

Henley's Magneto-Electric Machine.

Magneto-electric machine, illustrating the applicationof the electric current derived from magnets, to the pur-poses of electro-chemical decomposition, electro-metal-lurgy, &c.

The telegraphs have been tested in the worst insulatedline in the country, during the most unfavourable weather,and found to work any distance that it was possible to trythem, without any diminution of their power. Workingwithout the aid of a voltaic battery, they are alwaysready for use, without any preparation or expense. Fig.1 represents the telegraph with its cover, as in use; fig.2, the same with its cover removed, each consists of twoparts, one for producing electricity, the other for receivingit, and indicating the signals; the parts of each telegraphare alike. The first part consists of two compound barmagnets A A, the ends of each being capped with softiron, to bring the influence of all the plates to any parti-cular point. B B, two armatures, wound with fine-covered. copper wire, each placed on a separate axis, andmoved by the levers C C, seen projecting through thecase in fig. 1; the ends of the wire are carried from thearmature through the pieces of ivory in the axle to thewood base, and from thence to the distant instrument,every motion of the lever and armature producing a cur-rent of electricity, the downward motion giving a currentin one direction, and the upward motion a current in theopposite. The second part of the apparatus consists of adial, containing the alphabet and certain marks corre-sponding to the motions of the needles on the face of thedials; for instance, opposite to the letter A is seen asingle mark inclining to the left, signifying one motion ofthe left-hand needle; the letter B, two marks; letter C,three marks, signifying three motions of the same needle;the letter D, one mark to the right; E, two; and F,three ; G, one right and one left; L, one left; and onceboth needles together, and so on. Under the dial areplaced two electro-magnets D D, each having four poles,formed by two semicircular pieces of iron with a mag-netic needle, suspended freely within, placed on the sameaxis as the corresponding needle, or pointer, seen on thedial. The downward motion of the lever deflects thecorresponding needles of all the instruments that may beincluded in the circuit, as well as its own; the needlesremain so, until the lever is allowed to return by theforce of the spring E, when the needles all return totheir position, and this taking place with certainty,although the instruments may be at any distance.

The current obtained from the apparatus represented infig. 3 is very powerful, and capable of producing electro-chemical decomposition, and all the effects obtained froma powerful voltaic battery. The horse-shoe magnet A,with the evolving armature B, formed of hoop-iron, isplaced on the mahogany case C, and the whole fixed onthe iron framework, on which is suspended the largewheel and treadle, for giving motion to the armature bythe pulley D; the magnet has soft caps, and is arrangedthe same as the telegraph, so that the poles of the mag-net are always connected with some part of the iron of thearmature, and by that means it always retains its power.The two springs E E rub on the breakpiece F, whichis so arranged that the current flows in one direction ;the knob G moves a slide to divert the current to themercury cup H for showing the spark; the cam I movesthe point on the spring in and out,- the other knob is tomake a shock with the two terminals L L.

Electro-magnet capable of sustaining, when excited, 4tons: the sphere of attraction extends much further by-being made of iron hooping.

Large steel permanent magnet, weighing 6J cwts.,capable of sustaining about 1 ton.

[The received theory of magnetism is, that the attractingpower of the bar of steel, which we call a magnet, is dueto the circulation of electric currents around the bar. Itwas discovered by Faraday , that when a metallic mass ismoved in proximity to the poles, a current is induced init: upon this principle magneto-electric machines are con-structed. The soft iron armature, or keeper of the per-