Mr. Jay Hambidge of Boston and New York has for a number of years been engaged in a study of the proportions found, on the one hand, in the artistic designs of the early Egyptians and the Greeks, and on the other, in plant forms and in the human skeleton. The proportions thus obtained, with few exceptions, Mr. Hambidge finds belong to one of three systems according as they depend on the square root of two, of three, or of five. The human skeleton and most Greek vases and other objects of art of the best period are designed according to the root-five system. These three root systems, especially the latter, are conceived to be expressive of life, growth, and vitality and accordingly the term “dynamic symmetry” has been applied to them. During the decadence of Greek art the principles and methods of dynamic symmetry were lost, and hence much to the detriment of art were not used during the Roman period, the Middle Ages, nor since, until the labors of Mr. Hambidge led to their rediscovery. Art since the Greeks, it is maintained, is characterized by having “static symmetry,” the dimensions being commensurable one to another, and thereby lacks the vitality and subtlety of form which the earlier art possessed.