A bath made of water, 1 3/4 pint; silver nitrate, 2 oz.; potassium cyanide, 10 1/2 oz. Add sufficient Spanish white, or levigated chalk, in fine powder, to produce a thin paste, which is kept in a well-closed pot. This paste is spread by a brush or a pad of old linen, all over the surface of the reflector, and allowed almost to dry, when it is briskly rubbed over by another clean dry rag of old linen.
The difficulty of obtaining regular deposits of silver over articles which have parts soldered may be greatly obviated by scratch-brushing those parts dry, that is, without the usual liquid employed. This renders these refractory parts better conducting, provided that during the operation no impurities are left on these spots.
Take 1/2 oz. silver nitrate; dissolve in half a tea-cupful of cold water; add 1/2 lb. cream of tartar, with 1 1/2 lb common salt, beaten or ground fine. Mix and stir well together, adding water until it attains the consistence of a thick paste. Now lay the scale on a board, the brass or copper being previously well cleaned and cast off from fine sand-paper; rub the silvering on with your hand until it attains the appearance of silver, which will be a minute or so; now take the work off the board and rub a little wet whiting over it, wash out in clean cold water, and dry in saw-dust. If varnished with a thin coat of white hard varnish, reduced in spirits of wine, this will last for years. The above quantity of silvering used with care will silver six dozen brewers' thermometers, 14 in. long.