Neio Apparatus f of Heduciwj Chloride of Silver. 169 



leaving three inches of each hoard forming the legs of the frame. 



At the termination of these grooves passes horizontally a 

 narrow slit, half an inch deep, and along the whole length of each 

 board, into which a strip of metallic silver, i-inch wide and the 

 thickness of about a 3d. piece, is tightly fixed, projecting on 

 one side of the frame about 18 inches beyond each board. 



The 7 grooves already alluded to are for holding zinc plates 

 i-inch thick, 14 inches long, and 12 inches high, which rest on 

 both sides on the strips of silver which, as just described, are 

 jammed horizontally into the sides of the two boards ; a con- 

 nection is thus established between the 7 zinc plates and these 

 strips of silver. 



The second part of the apparatus consists of a wooden frame, 

 cut ' out of a solid board 1 inch thick, and supplied with two large 

 iron handles. The frame is the same length as the box holding 

 the zinc plates, but 3 inches narrower. It contains on each side 

 parallel to the direction of the zinc plates 12 slits, i-inch long, 

 which hold silver bands i-inch broad, and the thickness of a 3d. 

 piece. These silver bands are passed through the slits in the 

 board, so as to form on each side of it six loops, lli inches in 

 length, and -f wide ; the six loops on one side are exactly oppo- 

 site to those on the other side of the board, at a distance of about 

 9 inches. They are intended to hold the slabs of argentic 

 chloride, which are 12 inches long, 10 high, and about f inch 

 thick, and are put through these loops lengthways, projecting on 

 each end about 1 inch beyond the silver bands. 



The whole frame holds as before stated ; six of these slabs of 

 argentie chloride, which are placed between the six spaces formed 

 by the seven zinc plates, from which latter they are about i inch 

 apart on each side. 



The projecting horizontal strips of silver jammed into the 

 sides of the lower frame are then connected with the ends of the 

 silver forming the loops in which the argentic chloride is sus- 

 pended, and the whole apparatus thus charged is placed in a tub 

 filled with water. After a short time galvanic action is discernible, 

 the liquid gets gradually warmer, and a strong galvanic current 

 is observed. After about twenty-four hours the action has 

 nearly ceased, and the whole argentic chloride is found to be 

 completely reduced to metallic silver, which retains in the silver 

 loops the same shape, and, outwardly also, nearly the same 

 appearance as when first introduced as argentic chloride. The 

 latter contains always more or less chloride of copper (eliminated 

 together with the silver during the operation of refinage by 

 chlorine), which is reduced together with the chloride of silver. 

 In fact, this soluble chloride of copper helps to act as an exciting 

 liquor for the battery. In the first experiments a weak solution 

 of salt (chloride of sodium) was used as exciting liquor, but it 

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