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 the glory of having been one of the chemists before Lavoisier to prove that metals gain and do not lose weight on calcination in the air.

Pierre Joseph Macquer, Master of Pharmacy and Doctor of Medicine (born 1718, died 1784), came of a noble Scotch family who had settled in France on account of their adherence to the Catholic faith, made some notable chemical discoveries, and became director of the royal porcelain factory at Sèvres. He worked on kaolin, magnesia, arsenic, gold, platinum, and the diamond. The bi-arseniate of arsenic was for a long time known as Macquer's arsenical salt. Macquer was not quite satisfied with Stahl's phlogiston theory, and tried to modify it; but he would not accept the doctrines of Lavoisier. He proposed to substitute light for phlogiston, and regarded light as precipitated from the air in certain conditions. These notions attracted no support.

Guillaume François Rouelle (born near Caen, 1703, died 1770) was in youth an enthusiastic student of chemistry, the rudiments of which he taught himself in the village smithy. Going to Paris he obtained a situation in the pharmacy which had been Lemery's, and subsequently established one of his own in the Rue Jacob. There he commenced courses of private lectures which were characterised by such intimate knowledge, and flavoured with such earnestness and, as appears from the stories given by pupils, by a good deal of eccentricity, that they became the popular resort of chemical students. Lavoisier is believed to have attended them. Commencing his lectures in full professional costume, he would soon become animated and absorbed in his subject, and throwing off his gown, cap, wig and cravat, delighted his hearers with his vigour.