On the Construction of the Galvanic Battery. 73 



Fig. 3. Little slits are made at the lower angles and in the 

 middle, represented by a a a a, and the copper, being then bent 

 in the direction of the dotted lines, will produce the cell. It 

 is soldered on the lower and sloping sides. At the back of the 

 copper plate is soldered a piece of metal, w (iron, well var- 

 nished), by which it is suspended from the common bar repre- 

 sented by b. To one side also is soldered the slip s, connect- 

 ing it with the zinc of the contiguous pair. 



Fig. 4 gives a perspective view of a single element. The 

 copper cell, c, is represented with its suspensory piece, w, 

 attached to the bar, b, by two screws. The zinc plate z is 

 inserted in it, and prevented from contact by bits of wood with 

 a slit in one side, which have been boiled in copal varnish. 

 The copper plate suspensory and connecting slip are all well 

 varnished exteriorly, and the soldered part interiorly. 



Fig. 5 represents an end view of the whole instrument in 

 action. 



Fig. 6 giving the front of the same. T being a trough of 

 wood, well joined and lined with cement of wax and resin, at 

 each end of which is an upright support of wood, with a notch 

 in the top large enough to receive the end of the bar to which 

 the plates are attached ; wires proceeding from the opposite 

 poles convey the electric fluid where it is wanted. To suspend 

 the action, we have only to lift the bar out of the notches and 

 empty the fluid either into the same or another trough. To 

 renew it, plunge the cells until filled into the trough, and 

 lifting them out, place the ends of the bar into the notches. 

 I have constructed several instruments of different dimensions ; 

 and comparing their action with those upon other plans, find 

 a very great superiority of force in favour of my own. The im- 

 portance of insulation even for combustion is demonstrated 

 by placing in the circuit a wire of a given thickness, which, 

 while the plates remain immersed in the fluid, will show no 

 sign of combustion, but when they have been lifted out, is 

 instantly heated to a high degree. Should a" plate prove 

 defective, it may be replaced with but little trouble ; and an 

 immense power occupies but little space, the cells being only 

 half an inch wide, and not more than a quarter from each 

 other. The action also, being renewed or suspended at plea- 



