158 ANNUAL OF SCIENTIFIC DISCOVERT. 



THE BATTERY OF THE PROPOSED ATLANTIC TELEGRAPH. 



When the Atlantic cable is in position at the bottom of the sea, telegraphic 

 signals will be transmitted through it by induced magneto-electric currents, 

 on account of the superior velocity this kind of electricity possesses over the 

 ordinary voltaic current. These currents will be called forth by a somewhat 

 complicated agency, the primary element in which will be a voltaic combina- 

 tion of a very novel and ingenious kind, devised by Mr. Whitehouse. 



This battery, consisting of ten capacious cells, is made upon the Smee 

 principle, so fur as the adoption of platinized silver and zinc for its plates is 

 concerned ; but it differs from every form of combination that has hitherto 

 been in use, in having the plates of each cell so subdivided into subordinate 

 portions, that any one of these may be taken away from the rest for the pur- 

 pose of renewal or repair, without the action of the rest of the excited surface 

 of the cell being suspended for a single moment. 



So long as a fair amount of attention is given to the renewal of its zinc 

 element piece-meal, it is indeed literally exhaustless and permanent. This 

 very desirable quality is secured by a singularly simple and ingenious con- 

 trivance. The cell itself is formed of a quadrangular trough of gutta percha, 

 wood-strengthened outside, in which dilute acid is contained, the proportion 

 of acid to water being one part in fifteen or sixteen. There are grooves in 

 the gutta percha, into which several metal plates slide in a vertical position. 

 These plates are silver and zinc alternately, but they arc not pairs of plates 

 in an electrical sense. Each zinc plate rests firmly at the bottom on a long 

 bar of zinc, which runs from end to end of the trough, and thus virtually 

 unites the whole into one continuous extent of zinc, presenting not less than 

 two thousand square inches of excitable surface to the exciting liquid. 

 Each silver plate hangs in a similar way from a metallic bar, which runs 

 from end to end of the trough above, the whole of the silver being thus vir- 

 tually united into one continuous surface of equal extent to the face of the 

 zinc. The zinc docs not reach so high as the upper longitudinal bar, and 

 the silver does not hang down so low as the inferior longitudinal bar. The 

 battery is thus composed of a single pair of laminated plates, although to the 

 eye it seems to be made up of several pairs of plates. Nature has set the 

 example of arranging extended surface into reduplicating folds, when it is 

 required that such surface shall be packed away in a narrow space at the 

 same time that a large acting area is preserved, in the laminated antennas 

 of the cockchafer. The antenna, indeed, are the types of the Whitehouse 

 battery. If any one of these reduplicated segments of either kind of metal 

 is removed, the remaining portion continues its action steadily, the effect 

 merely being the same that would be produced if a fragment of an ordinary 

 pair of plates were temporarily cut away. The silver lamina; are of con- 

 siderable thickness, and securely "platinated " all over ; that is, platinum is 

 thrown down upon their surfaces in a compact metallic, form, and not merely 

 in the black pulverulent state ; consequently, they are almost exempt from 

 wear. Each zinc lamina is withdrawn so soon as its amalgamation is 

 injuriously affected, or so soon as its own substance is mainly eaten away 



