The solder for joints requires to be of some metal more fusible than that of the substances to be joined.

For Copper, usual solder 6 to 8 parts brass to 1 of zinc; 1 of tin sometimes added.

A still stronger solder, 3 parts brass, 1 of zinc.

To prepare this solder. - Melt the brass in a crucible, when melted add in the zinc, and cover over for 2 oi 3 minutes till the combination is effected, then pour it out, over a bundle of twigs, into a vessel of water, or into a mould composed of a number of little channels, bo that the Bolder may be in long strips convenient for use.

Brass things alone will answer very Well.

To braze with this solder.- Scrape the surfaces perfectly clean, and secure the flange or joint carefully; cover the surfaces to be brazed with borax powder moistened; apply the solder, and melt it in with the flame of a clear coke fire from a smith's hearth; particular care being taken not to burn the copper.

Iron and brass are soldered with spelter, which is brass and zinc in equal parts; the process being performed in a manner similar to the above. For ironwork, however, sometimes rather differently; the articles are fixed in their position, and the solder applied, a covering of loam is then put over all to exclude the air, the work thus prepared is then put into the fire a sufficient time to melt the solder in.