Page:Popular Science Monthly Volume 51.djvu/549

Rh the tusk. To the regularity and smallness of these canals ivory owes its elasticity, firmness, and fineness of grain; to their curvatures and eccentric direction—plainly visible in cross-cut sections—are due those beautiful cloudings and delicate markings which give value to, and readily distinguish the real from the imitated article.

Ivory is extremely hard and heavy—the very name, a Latin derivative from barrus, an elephant, so called from a Greek word meaning heavy. It is difficult to cut, requiring the sharpest and hardest of tools, but yields readily to the saw, the lathe, the file. Owing to its value, which is so constantly increasing that it now ranks with the "precious" substances, the greatest care is taken to avoid waste in manipulation. The cutting is effected with thin saws. Large plates of veneer have been obtained by the "reciprocating" saw, cutting a spiral shaving round the tusk. There is an account of one thus produced which was forty feet in length and twelve inches wide. Polishing is done by the use of various powders.

Ivory is dead pearly white in color, which sometimes changes with age and exposure to yellow, brown, or black. This natural whiteness is exquisitely delicate, and, as an enthusiast in ivories expresses it, "bears a great resemblance to the brightest tint of the human skin, which latter is the most beautiful hue in Nature." On account of the yellowing with age, there have been many recipes for restoring its whiteness, but none have proved satisfactory. A fortune is in store for the inventor or discoverer of the "happy medium." The opacity and elasticity of old ivory can be partially restored, at least to be useful for some purposes, by boiling in a solution of gelatin.

The existence of statues and of plaques of ivory larger than could be cut from any known tusk, render it probable that ancient workers possessed some method of bending or molding. It can be made flexible by a bath of phosphoric acid, but at the expense of many of its properties. It will also take a variety of dyes without interfering with its polish, particularly if the actual matrix or organic matter is stained.

The tusks of the elephant are an elongation of the upper incisor teeth, which may attain to enormous development; the largest are those of the extinct mammoth; some specimens have been found in Siberia more than twelve feet in length and two hundred pounds weight. There was a noted one of particularly fine quality, weighing one hundred and eighty-six pounds, that was cut up into piano keys.

Among the modern elephants the African possesses the largest tusks, often nine or ten feet in length, and weighing one hundred and sixty pounds each. A pair of African tusks was exhibited