chair in which the hero sat during the review, or to fight for shreds of the flags and awnings that decorated the platform. Sporadic social reform movements take the form of crazes and illustrate the same laws. One recalls the Woman’s Crusade in 1873, the result not of a rational plan but of imitation, and the Granger movement and the Farmers’ Alliance and the greenback craze and the silver craze and many others. Since Aristotle we have been told that man is a social animal and that to study him as he really is we must not isolate him from society. The evident truth of this may lead us to forget that it is but a half truth and the uncritical acceptance of it will lead us wholly astray in our sociological study. The inference which we seem compelled to draw from studies in social psychology is that social man is, in his ethical and intellectual development, many stages behind the individual man. The progress of civilization is a slow, painful, upward climbing, in which individuals are the thinkers, the planners, the promoters and the leaders. The mind of society, on the other hand, using the phrase in the sense defined, is an imitative, unreflective, half-hypnotic, half-barbaric mind, always acting as a drag upon the upward and forward movement, and, in times of crazes, epidemics and social cataclysms, gaining temporary dominance and causing disastrous relapses to a lower plane of civilization. SOME PHASES OF THE EARTH’S DEVELOPMENT IN THE LIGHT OF RECENT CHEMICAL RESEARCH. BY PROFESSOR EDWARD RENOUF. JOHNS HOPKINS UNIVERSITY. In the following pages an effort is made to apply some of the results of recent chemical research to the earlier history of the earth. It is hoped that the main facts brought out may be readily grasped by those who have never studied chemistry, and that each link in the chain of events will be made evident to those who have mastered the rudiments of this science. Chemical action involves change of composition. Substances more or less complex may be broken down into simpler substances, or from several simpler substances a complex substance may be built up. From the complex ore of copper found in nature the simple element copper is obtained. From the elements sulphur and oxygen and the simple substance water the complex sulphuric acid is built up. Within the last few years the high temperature of the electric arc--the heat generated by a powerful electric current playing between two carbon poles--has been employed in bringing about chemical changes which do not occur at ordinary temperatures nor at those obtainable by burning fuel. The electric furnace is used industrially to make calcium carbide from lime and coke, carbon silicide (carborundum) from coke and sand, and the metal aluminum from its compounds.