Page:Popular Science Monthly Volume 51.djvu/548

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POPULAR SCIENCE MONTHLY.

oping a pure duodecimal system, combined the seximal with the decimal in a multiplicative manner, and so developed a sexagesimal system.

The reader may take his choice between these two attempts to explain what, in any case, must be regarded as a remarkable phenomenon. Without denying that either may possibly be the true explanation, the writer is of the opinion that much additional evidence will be required to finally solve the question. With the rapid advance that is now being made in the field of Babylonian antiquities it is not impossible that the needed information will be forthcoming.

 

IVORY: ITS SOURCES AND USES.
By N. B. NELSON.

THOUGH an animal product, its combinations with wood, particularly ebony, from the earliest history, and the similarity of its uses and working in the way of carving, turning, veneering, and inlaying, make ivory an interesting material to joiners, decorators, and builders.

In texture, elasticity, hardness, peculiar markings or cloudings of the grain, and several other particulars, ivory is very like the harder woods, and, being of similar durability, is very suitable to "make up" in mosaics, inlaying, etc., with them, making a companion commodity.

Ivory is really dentine—that substance, not unlike bone, of which teeth principally consist. By usage it is restricted to the dentine of those teeth which are large enough for industrial purposes—viz., the tusks of the elephant, hippopotamus, walrus, narwhal, and some varieties of whales. These forms of ivory differ about as the hard woods differ: the elephant ivory, by its size and quality, is best suited for all purposes; that of the hippopotamus is harder and finer, but owing to its hollowness can only be used for small articles. The old Norsemen used extensively the tusks of the walrus, and when "whaling" was at its best the sperm whale was sought almost as much for the ivory as for the oil. It was the writer's fortune to examine a whale's tooth which was nine or ten inches in length and six or eight in circumference, and seemed solid ivory of a beautiful quality, but so hard as to defy every effort of its owner, who was an expert carver, spoiling, as he expressed it, his "tools and temper."

Ivory, consisting chemically of an organic matrix or growing element, phosphate and carbonate of lime, is permeated by numerous exceedingly fine canals, starting from the organic or pulp cavity and running generally outward to the circumference of