to be placed under the hammer.


136. COMPOSITION USED IN WELDING CAST IRON

Take good clear white course sand, 3 parts; refined solton, 1 part;
fosterine, 1 part; rock salt 1 part; borax, 1 part; mix all
together. Take 2 pieces of cast iron, heat them in a moderate
charcoal fire, occasionally taking them out while heating, and
dipping them into the composition, until they are of a proper heat
to weld, then at once lay them on the anvil, and gently hammer them
together, and if done carefully by one who understands welding iron,
you will have them nicely welded together. One man prefers heating
the metal, then cooling it in the water of common beans, and heating
it again for welding.


137. CAST IRON CEMENT

Take of clean borings or turning of cast iron, 16 parts; of
sal-ammoniac, 2 parts; and flour of sulphur, 1 part; mix them well
together on a mortar, and keep them dry. When required for use,
take 1 part of the mixture, and 20 parts of clean borings, mix
thoroughly, and add a sufficient quantity of water. Note.--A little
grindstone added improves the cement.

138. CASE HARDENING

This is the conversion of the surface of wrought iron into steel,
for the purpose of adapting it to receive a polish, or to bear