The variety known as liver or sulphur is generally used, and imparts a reddish brown colour to the silver, the colour being darker the darker the solution. It should be worked at 60 or 70 per cent. The stronger the solution the blacker the colour. If ammonium carbonate (20 grains) is added to the above formula and is worked hot, a black colour appears upon rubbing with a very fine wire brush. It takes on the colour of black lead. Colouring of brass:

This will turn brass a very beautiful blue-black colour. Copper assumes a very beautiful tint from this solution.

Cement for engravers: Melt best pitch in an iron pot and when completely liquid stir in a mixture composed of two thirds of raw pitch and one third plaster of paris. Make a lot of ten pounds. Add one half pound mutton tallow, boil and mix thoroughly. Should this be too soft, add plaster of paris until you get the desired hardness:

To polish enamel: After rubbing it down with the corundum file, take a small rod of tin or pewter and after anointing it with fine Tripoli or rotten-stone, grind the surface of the enamel evenly with the tin or pewter rod. Next take a stick of lime wood and use that with the rotten-stone in the same way and finish with putty powder and stick covered with chamois skin.

To unsolder a piece of work: Paint those joints which are not to be unsoldered with a mixture of clay water, to which add a little common salt. When dry, scrape the part to be unsoldered and paint it with borax. Now heat till solder melts, pick off with pliers or knock it off with a gentle tap. The borax adds flux, thus helping the solder to run at a melting temperature.

MACHINERY IN METAL WORK: DIE MAKING

Most of the jewellery that we see nowadays and also much of the metal work is made under presses or drop hammers. As was shown in the making of the mould for the round copper tray, the skill lies in the making of the design and the making of a mould to fit the design.