To temper mining picks heat them in charcoal fire until red-hot and then immerse in cold rain water and keep there until nearly cold. The use of salt water for this tempering, as is done by many blacksmiths, is erroneous, as there should be no salt in the water, but the same should be cold. If the water is warm, put in a little ice.
The causes of the lamp explosions so frequently reported is the use of poor oil. A simple plan for testing the flashing point of kerosene oil used for illumination is as follows: No kerosene is fit for use in lamps Which flashes at a temperature less than 110 degrees Fahr. To test oil, fill a tumbler full of water at 110 degrees Fahr., stir in a tablespoonful of kerosene, and leave until the oil reaches the same temperature. Pass a lighted match over the oil as it floats on the surface, and, if the oil does not ignite it may be safely-used. If it flashes at that temperature discard it.
A simple, practical way for testing Russia iron, so as to distinguish readily between the genuine article and the inferior imitations that are in the market: The genuine article is known by its fine black lustre and small granulation of the surface in reflected light. Otherwise by its toughness in bending with and across the grain.
Tiers' argent is an alloy composed of:
66 66-100 parts Aluminum, 33 33-100 parts Silver.
The metal tin can be burned as easily as paper, and to do it makes an interesting parlor experiment. A candle, blow-pipe and tin foil are necessary. With the blow-pipe direct the flame of the candle against a strip of tin foil, and it will readily take fire and burn with a brilliant light, the melted incandescent globules falling to the table and dancing about in a very curious manner. It will be noticed that the product of the combustion of the tin is a white powder, the oxide of tin, and it was observed many years ago that this calx, as it was called, weighed more than the original tin.
To discover if an article is tin foil or lead foil plunge same in a bath of concentrated sulphuric acid. This will dissolve tin, while lead will remain undissolved.
For putting a thin coat of tin on common black iron, for cold tinning, the following is recommended: Dissolve block tin in muriatic acid and add a little mercury, or one part of tin, two of zinc and six parts of quicksilver. Mix tin and mercury together until they form a paste. Clean the plate, carefully removing all grease, then rub with a piece of cloth moistened with muriatic acid and immediately apply a little of the amalgam to the surface, rubbing it with the same rag.
To tin band iron make a tinning bath as follows: Dissolve with the aid of heat, in an enameled cast-iron kettle, ammonical alum, 11 oz., and fused proto-chloride of tin 1-3 oz. in 4 1/2 gallons of soft water. Clean and rinse the iron to be tinned in cold water, and immerse in the solution as soon as it boils. This process will give a thin coating of tin of a dead lustre, which may be rendered bright by friction. The bath should be maintained at proper length by small additions of proto-chloride of tin.