Take of borax, 10 parts; sal-ammoniac, 1 part; grind or pound them roughly together, then fuse them in a metal pot over a close fire, taking care to continue the heat until all spume has disappeared from the surface, when the liquid appears clear, the composition is ready to be poured out to cool and concrete; afterward being ground to a fine powder. To use this composition, the steel to be welded is raised to a heat, which may be expressed by bright yellow, it is then dipped among the welding powder, and again placed in the fire until it attains the same degree of heat as before, it is then ready 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 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 using this solder.

142. SOLDER FOR IRON

The best solder for iron is good tough brass, with a little borax.

143. SOLDER FOR COPPER

Take of brass, 6 parts; zinc, 1 part; tin, 1 part; melt all together, mix well, and pour out to cool.

144. SOLDER FOR STEEL JOINTS

Silver, 19 parts; copper, 1 part; brass, 2 parts; melt all together.

145. HARD SOLDER

Fuse together 2 parts of copper, and 1 of zinc.

146. SOLDER FOR SILVER

Fuse together 5 parts of silver, and 1 part of brass.

147. GOLD SOLDER No. 1

Take of gold, 4 parts; silver, 3 parts; copper 1 part; and zinc, 1 part.

148. GOLD SOLDER No. 2

Take of gold, 3 parts; silver, 3 parts; copper, 1 part; zinc, 1/2 part.

149. GOLD SOLDER No. 3

Take of gold, 2 parts; silver, 3 parts; copper, 1 part; and zinc 1/2 a part.

The gold, silver, and copper must be fused in a crucible before the zinc is added, or else you cannot keep them in the vessel while heating. When all are completely fused, they must be well stirred, and run into bars. Solder No. 1 is for gold 16 carats and upwards; No. 2 is for that 14 carats fine; and No. 3 for lower qualities. If more zinc is added, it will fuse at a lower heat, but the colour is not so good.

150. MOCK GOLD

Fuse together 16 parts of copper, 7 of platinum, and 1 of zinc. When steel is alloyed with 1/500 part of platinum, or with 1/500 part of silver, it is rendered much harder, more malleable, and better adapted for all kinds of cutting instruments. Note.--In making alloys, care must be taken to have the more infusible metals melted first, and afterwards add the others.

151. BRITANNIA METAL

Take 4 parts of brass, and 4 parts of tin; when fused add 4 parts of metallic bismuth, and 4 parts of metallic antimony. This composition is added at discretion to metallic tin, according to the quality you wish to make.

152. BLANCHED COPPER

Melt together 8 parts of copper and a half part of arsenic.

153. COMMON PEWTER

Melt together 4 parts of tin and 1 part of lead.

154. BEST PEWTER

Melt together 100 parts of tin and 17 of antimony.

155. A METAL THAT EXPANDS IN COOLING