friction, &c. The best method in the world of effecting this is by
heating the iron to cherry red in a close vessel, in contact with
carbonacious material, and then plunging it into cold water. Bones,
leather, hoofs, and horns of animals, are best for this purpose,
after having been burnt or roasted, so that they can be pulverized.
Soot is very frequently used; it answers, but not so well.


139. TO SOFTEN IRON OR STEEL

Either of the following simple methods will make iron or steel as
soft as lead: 1. Anoint it all over with tallow, temper it in a
gentle charcoal fire, and let it cool of itself. 2. Take a little
clay, cover your iron with it, temper in a charcoal fire. 3. When
the iron or steel is red hot, strew hellebore on it. 4. Quench the
iron or steel in the juice, or water, of common beans.


140. SOLDER FOR LEAD

Melt 1 part of block tin, and when in a state of fusion, add 2 parts
of lead; if a small quantity of this, when melted, is poured upon
the table, there will, if it be good, arise little bright stars upon
it. Resin should be used with this solder.


141. SOLDER FOR TIN

Take 4 parts of pewter, 1 of tin, and 1 of bismuth, melt them
together, and run them into thin slips. Resin is also employed in