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We publish the following by request; it was published before in volume 5, but it will be new, we have no doubt, to some thousands of our present subscribers. The receipt is not a new one, but a good old one, none the worst' for a little wear. When the filings of soft cast-iron are melted in a crucible with borax, which has been previously calcined in order to get rid of the water it contains, a hard shining, black pitch-like soldering substance is obtained, being glass of borax colored black with iron. Sal ammoniac having been applied to the internal joining, or between the overlapped edges of thin sheet iron, some of this black solder being powdered is to be laid along a short portion of the joint, and as soon as it is melted over a clear forge fire, the soldered part is to be placed on the beak of an anvil hand, as long as the heat permits. More of the powiler is then to be laid upon the adjoining part of the joining, until the whole of the seam is soldered. Another method, which has been published for this purpose, is to melt five ounces of borax in an earthen crucible, and when melted, to add half an ounce of sal ammoniac, and pour the melted matter upon an iron plate. When cold, it will appear like glass, and is to be powdered and mixed with an equal quantity of unslaked lime. The iron or steel being heated to a red heat, a little of the above powder is to be sprinkled on the surface, where it will melt like sealing wax. The iron or steel is then to be again heated, but considerably below the ordinary welding heat, then brought to the anvil, and hammered until the sufaces are perfectly united.
