. Journal. e acidified and precipitatedas chloride. Desilverising acid or strippingsolution must, if necessary, be diluted before pre- cipitation, and the filtrate obtained must beneutralised or further diluted before passing tothe drain. The precipitated chlorides may bedrained and 6ent to the refiner, or reduced tometallic silver with 6crap iron. Solutions from platinum-plating, which oftencontain much phosphate, can be precipitated n ithzinc dust, but complete reduction is difficult. Insome workshops electrolytic reduction, using aninsoluble anode, is carried out and found satis-factory. Fi
. Journal. e acidified and precipitatedas chloride. Desilverising acid or strippingsolution must, if necessary, be diluted before pre- cipitation, and the filtrate obtained must beneutralised or further diluted before passing tothe drain. The precipitated chlorides may bedrained and 6ent to the refiner, or reduced tometallic silver with 6crap iron. Solutions from platinum-plating, which oftencontain much phosphate, can be precipitated n ithzinc dust, but complete reduction is difficult. Insome workshops electrolytic reduction, using aninsoluble anode, is carried out and found satis-factory. Filtration of Precipitates.—A few instructions onthe making of square calico filters for these precipi-tates may be of use. A square wooden frame is made of such sizo thatits corners will just rest on the edge of the deepcircular vessel into which it is proposed to frame may be, for example, 14 in. square and3 in. deep and made of batten 1 in. thick, thusleaving an inner opening of 12 in. Fio. view ol alter. Scale J. From a piece of new. closely woven calico, washedto remove dressing and dried, cut an exact squareol -I in. side, mark the middle of each side andthe middle of each upper edge of the frame, whit hmay be conveniently standing on the circularvessel < Kiu- I). Taking the nnddlo of each cloth-edge in turn, and doubling J in. underneath tostrengthen it, fasten it temporarily by means ofcopper tacks to the middle-points, F, G, H, J, oftho upper edges of tho frame, leaving tho slackof the cloth hanging inside. On the side AH, draw the cloth-edge tight fromtral tack, double } in. underneath as before,and fasten it with a tack almost at the corner B;repeat this with the other half of the same edgetowards corner A. Turn the frame round and dealsimilarly with side CD. These two sides are nowfinished and are represented in the diagram of theunfolded cloth taken from the framo by the sameletters (Fig. 2). Taking side BC, hold the cloth-edge in one h
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
