40	THE DIAMOND
	of Nature is such that no demand of man can arise for which there is not a possible supply. If he needs heat, and the sun's rays are insufficient, he learns to kindle fires and get the needed heat by burning wood; as the wood fails, he discovers coal; before the coal measures are exhausted, he finds there is a full supply to be developed from electricity, and so on. It is not possible for a man to need more than Nature can supply, and in fact most if not all of man's needs, are created by the supplies which surround him. Supply and de­mand are the working phenomena of the principle in Nature which constantly scatters and re-unites the ele­ments, making out of heterogeneous masses, homo­geneous combinations and vice versa, thereby insuring the continuity of life and progress.