246 On a Voltaic Battery charged with Sulphate of Copper, 



with amalgamated zinc, which is well adapted to the use of 

 sulphate of copper; it is more (Economical in its construction* 

 than any now in use, and possesses this great advantage, that 

 the zinc when worn out may be easily replaced. Fig. 6 shows 

 the zinc plate, which must be tinned on the top Af prior to 

 the amalgamation of the rest of the plate; B B are two slips 

 of wood grooved out to within threeTourths of an inch of the 

 bottom, and intended to retain the zinc plate in its proper 

 position. The copper plates are formed into cells, as repre- 

 sented in fig. 7, five inches square and one inch wide : E E 

 are two ears of copper, by which the cell is suspended in its 

 place ; A is a slip of copper to form a connection by means 

 of solder to the zinc plate in the adjoining cell. The cells 

 are painted on the outside to protect them from the action of 

 acid. The zinc plates do not descend lower than within three 

 fourths of an inch of the bottom of the cells, so that the space 

 left may contain the deposit resulting from the decomposition 

 of the sulphate of copper. The cells are supported in a long 

 wooden frame by the ears E E and retained in their place by 

 tacks driven through them as represented in fig. 9. Fig. 8 

 represents a contrivance by which the charge may be renewed 

 while the battery is in action : at the top of each cell may be 

 placed a lip or spout L, a quarter of an inch deep; these 

 must overhang a wooden gutter running the length of the 

 frame. The solution must be renewed with a funnel having a 

 long neck, the long end being inserted nearly to the bottom of 

 the cell ; when fresh solution is poured in, the spent licjuor 

 will run out of the lip into the gutter. 



Immediately after a series of experiments the battery must 

 be emptied, and the plates well cleaned by dashing water be- 

 tween the cells. If this be not immediately attended to it will 

 be exceedingly difficult to remove the deposit from the cells. 

 A Cruickshanks's battery is best cleaned by laying it on its 

 side. I remain. Gentlemen, yours, &c. 



110, Bunhill Row, Dec. 7, 1836. Warren De LA RuE. 



P.S. The fact related in your first note (vol. ix. p. 48 i) 

 shows that Professor Daniell had no intention of employing 

 sulphate of copper in an ordinary battery ; he inmiersed a 

 zinc plate in sulphate of copper and found that there was local 

 action, from the deposition of copper ; but he went no further. 



• The one I have, cost altogether 3/.; but as I put this together myself, 

 a similar battery constructed by workmen would of course be rather more 

 expensive. 



t This is effected by filing the top smooth, wiping it over with a little 

 muriate of ammonia, and then dipping the top in a ladle of melted tin, a 

 little tallow being placed on the tin to prevent the surface from oxidating. 



