Ivory is of cellular, not fibrous, construction. Through the center of the tusk runs the great nerve of the tooth. The structural cells build up around the nerve. Surrounding the nerve, the cells are small and more compact. As the tusk grows in length on the living elephant it also expands; but the cells grow larger and less compact as the tusk expands in circumference. It is quite apparent, therefore, that the weight centers around the nerve. To have a perfectly balanced ball, one that will roll true in every direction, the ball must be so turned out of the tusk that the nerve center runs exactly through the middle of the ball. The process is as follows: The tusk is sawed into blocks about 2-3/4 inches in size. These are of irregular cylindrical form, depending on the form of the tusk’s circumference. Only that portion of the tusk can be used, the diameter of which is greater than the intended diameter of the ball. The rest of the tusk is used for ornaments, piano keys, etc. At least six inches from the point of the tusk must be discarded because the circumference is too small. The hollow part at the base of the tusk must also be discarded. There are defects discovered only when the ball is being turned or the segments cut. For all of the discarded portions and the fragments and shavings from the segments when the ball is turned, the manufacturer receives less than one-fourth of the price per pound which he paid for the whole tusk. A segment is placed in a lathe--with the nerve center resting on the lathe point. The ball is then either turned down from the outside or cut out with an ingeniously constructed curved cutter from the inside of the segment. In the latter operation the ball lies loose in the center of the segment, which must be sawed in half to release it. Ivory seasons only to a slight depth. The thin seasoning on the surface seems to act as a shell which keeps raw the substance underneath. For this reason, when a ball is turned out of the tusk and the raw ivory thus exposed, the ball is stored away in a room of even temperature for about a year, that it may properly season before being finished. The red ball is dyed after seasoning, and at the time of final turning called finishing. Another peculiarity about ivory is the fact that, owing to the cellular construction, in seasoning the ball never contracts at the nerve ends, but always around the other circumference, termed the “belly.” Therefore, when the balls are turned, the circumference around the “belly” is made greater than around the nerve ends, to allow for the shrinkage in the former. Each manufacturer carefully guards the secret of his allowance, which is made according to his experience and knowledge of ivory seasoning variations. After seasoning, the balls are smoothed with shagreen and polished.