From a table compiled by kolb, one of the secretaries in the Imperial Telegraph Department of Germany, it seems that of the 12,350/. spent during the year 1881-82 upon the 127,166 galvanic cells in use, 2727/., or about 22 per cent., were recovered by the sale of the battery residues, consisting of copper, zinc, and lead salts. It has been customary to sell these products by auction twice a year. The Government does not guarantee any fixed percentage of metal in these salts, but the amount varies very slightly. The normal cell of the German telegraph offices is a modified Daniell of a simple and cheap kind. The zinc electrode is formed of a ring, hanging down from the edge of a glass vessel to half its depth. On the bottom lies a rectangular plate of lead, to which a vertical stout iron wire, encased in sheet lead, is soldered, making the other electrode. The glass is filled with zinc sulphate solution, and a few crystals of copper sulphate are from time to time dropped into the liquid. Of these materials the zinc ring is, of course, most subject to deterioration. Thus the above-mentioned 127,166 cells aquire nearly 80,000 new zinc rings, against 730 lead sheets and 910 lead plates.
The copper sulphate forms the largest item in the annual expenditure, amounting to 8000/. During the 4 years which the table comprises, from 1878 to 1882, the number of cells had increased by nearly 20,000. (Engineering.)