TURNING WOOD INTO METAL.
Our readers may not be aware of a process whereby wood can be almost turned into metal; that is to say the surface becomes so hard and smooth that it is susceptible of a high polish, and may be treated with a burnisher of either glass or porcelain. The appearance of the wood is then in every respect that of polished metal, and has the semblance of a metallic mirror, only with this peculiar and important difference, that, unlike metal, it is unaffected by moisture. The process by which this curious fact is arrived at may be briefly described. The wood is steeped in a bath of caustic alkali for two or three days, according to its degree of permeability, at a temperature of between one hundred and sixty-four and one hundred and ninety-seven degrees of Fahrenheit. It is then placed in a second bath of hydrosulphate of calcium, to which a concentrated solution of sulphur is added after twenty-four or thirty-six hours. The third bath is one of acetate of lead at a temperature of from ninety-five to one hundred and twenty-two degrees of Fahrenheit, and in this the wood remains from thirty to fifty hours. After a complete drying, it is then ready for polishing with lead, tin, or zinc, finishing the process with a burnisher, as already mentioned, when the wood, apparently, becomes a piece of shining polished metal. This curious process we are told is the invention of a German named Rubennick.