Mode of beginning the study

Whatever may be the principles of division and classification preferred in the general system of chemical studies, it is agreed by almost all chemists that the preliminary and fundamental study should be the successive and continuous history of all the simple bodies. The plan of M. Chevreul is an exception to this, his method being to proceed at once from the study of each element to all the combinations, binary, ternary, etc., that it can form with those already examined; confining himself, however, to compounds of the first order. This plan has the advantage that simple bodies are more completely known from the beginning than by the usual method, which scatters through the different parts of the science the most important chemical properties of each of them. But, on the other hand, the history of any element remains incomplete; a factitious inequality is established among chemical researches into different elementary substances; and the didactic inconvenience which M. Chevreul proposed to escape seems to be unavoidable, under any method. On no plan can any chemical history be completed by a first study. The provisional information obtained by a first study must be followed by a revision which allows us to take into consideration the whole series of phenomena relative to each substance. The question is merely a didactic one, only of secondary importance in this work, though of great practical interest.