44	PEARLS
	The increase in value of pearls has been going on during the last twenty years very rapidly, and the increase has been far greater than is the case with diamonds or even with emeralds. The causes for this advance in price are better known than in the case of diamonds, and the probable value of pearls in the future can there­fore be more definitely forecasted. Regard­ing these points I will draw largely from a personal letter from Mr. Ludwig Nissen, of New York: In brief, then, the cause for the advance in price of pearls is simply that the supply is now absolutely inadequate to meet the demand. The supply is chiefly from two sources, — the fisheries and the accumulated stores of the great Indian rajahs. The fisheries, the only primary source, are gradually being exhausted. In the last five years, statistics show that there has not been an average of ten million dollars' worth of pearls from all the fisheries combined, while much more than ten million dollars' worth of pearls are sold annually in New York City alone. Furthermore, there has not been a new pearl fishery discovered in the last fifty years. This exhaustion of the fisheries has been accelerated by the methods used. In former years divers went down to the bottom of the