And every paladin and peer,
At Roncesvalles died!"
I quote from memory, and have not the poem.
F. C. B.
PHOTOGRAPHIC CORRESPONDENCE.
Recovery of Silver.—As many correspondents of "N. & Q." have asked how to recover the silver from their nitrate baths when deteriorated or spoiled, perhaps the following hints may be acceptable to them. Let them first precipitate the silver in the form of a chloride by adding common salt to the nitrate solution. Let them then filter it, and it may be reduced to its metallic state by either of the three following methods.
1. By adding to the wet chloride at least double its volume of water, containing one-tenth part of sulphuric acid; plunge into this a thick piece of zinc, and leave it here for four-and-twenty hours. The chloride of silver will be reduced by the formation of
chloride and sulphate of zinc, and of pure silver, which will remain under the form of a blackish powder, which is then to be washed, filtered, and preserved for the purpose of making nitrate of silver.
2. The chloride of silver which is to be reduced is put into a flask with about twice its volume of a solution of caustic potash (of one part of caustic potash to nine of water), in which a small portion of sugar has been dissolved. Let it boil gently. The operation is complete when the blackish powder which results from this process, having been washed in several waters, is entirely soluble in nitric acid, which is easily ascertained by experimenting on a small quantity. This powder is to be preserved in the same way as the former for the purpose of converting it into nitrate of silver.