Respiration is a kind of combustion whereby the temperature of the body is maintained. It consists simply in the transference of the phlogiston of the body to the air. If we attempt to breathe in a confined space, the air becomes eventually saturated with the phlogiston, and respiration stops. The various manifestations of chemical action, in like manner, were attributed to this passing to and fro of phlogiston. The colour of a substance is connected with the amount of phlogiston it contains. Thus, when lead is heated, it yields a yellow substance (litharge); when still further heated, it yields a red substance (red lead). These differences in colour were supposed to depend upon the varying amount of phlogiston expelled. The doctrine of phlogiston was embraced by nearly all Stahl’s German contemporaries, notably by Marggraf, Neumann, Eller, and Pott. It spread into Sweden, and was accepted by Bergman and Scheele; into France, where it was taught by Duhamel, Rouelle, and Macquer; and into Great Britain, where its most influential supporters were Priestley and Cavendish. It continued to be the orthodox faith until the last quarter of the eighteenth century, when, after the discovery of oxygen, it was overturned by Lavoisier. During the sway of phlogiston chemistry made many notable advances—not by its aid, but rather in spite of it. As a matter of fact, until the time of Lavoisier few, if any, investigations were made with the express intention of testing it, or of establishing its sufficiency. When new phenomena were observed the attempt was no doubt made to explain them by its aid, frequently with no satisfactory result. Indeed, even in the time of Stahl, facts were known which it was difficult or impossible to reconcile with his doctrine; but these were either ignored, or their true import explained away. Although, therefore, these advances were in no way connected with phlogiston, it will be convenient to deal with the more important of them now, inasmuch as they were made during the phlogistic period. With the exception of Marggraf, Stahl’s German contemporaries contributed few facts of first-rate importance to chemistry. =Pott=, who was born at Halberstadt in 1692 and become Professor of Chemistry in Berlin in 1737, is chiefly remembered by his work on porcelain, the chemical nature and mode of origin of which he first elucidated. =Marggraf=, born in Berlin in 1709, was one of the best analysts of his age. He first clearly distinguished between lime and alumina, and was one of the earliest to point out that the vegetable alkali (potash) differed from the mineral alkali (soda). He also showed that gypsum, heavy spar, and potassium sulphate were analogous in composition. He clearly indicated the relation of phosphoric acid to phosphorus, described a number of methods of preparing that acid, and explained the origin of the phosphoric acid in urine. Of the Swedish chemists of that period, the most notable was Scheele.