BERTRAND, a celebrated chemical philosopher, was born at Bayonne in the year 1761. He very soon discovered a strong predilection for the sciences, to cherish which he had every thing in his father's house that could reasonably be desired, and there acquired the elements of that art for which he was afterwards so famous. His subsequent progress took place under Darcey, who admitted him amongst the pupils attached to the chemical laboratory of France. Five years of intense application under such a master gave him a stock of knowledge very uncommon at his years. As a convincing proof of this, when only twenty-one years of age, he published a number of valuable observations on arsenic acid; proving, contrary to the opinion of Macquer, that sulphuric acid distilled from the arseniate of potash disengages the acid of arsenic.

Encouraged by the success which had attended his first chemical labours, he communicated his remarks on the crystallization of sulphur, cinnabar, and the deliquescent salts; as also the examination of zeolites, particularly the false zeolite of Freyburg, which he discovered to be merely an ore of zinc. He likewise made observations on the oxygenated muriatic acid, in reference to the absorption of oxygen; on the formation of other acids, chiefly the nitric and the acetic; and a number of memoirs on the operation of phosphorus made in the large way, its conversion into phosphoric acid, and its combination with sulphur and most metallic substances.

It was by his operations on phosphorus that he burned himself so severely as nearly to endanger his life. Immediately on his recovery he began the analysis of different varieties of plumbago from France, England, Germany, Spain, and America, and gave both novelty and interest to his work, even after the labours of Scheele on the same subject had made their appearance. The analysis of carbonate of barytes led him to make experiments upon animals, from which he discovered that this earth is a real poison, in whatever way it be administered. Strontites was also analysed by this celebrated chemist, and found to contain a new earth.

Pelletier discovered a process for preparing verditer in the large way, equal, it is said, in beauty to that which is manufactured in England. He was likewise amongst the first who showed the possibility of refining bell-metal, and separating the tin. His first experiments were performed at Paris, after which he went to the foundery at Romilly to prove their accuracy in the large way. He was soon after this admitted a member of the Academy of Sciences at Paris, and subsequently accompanied Borda and General Dabouville to La Fère, to assist in experiments upon a new species of gunpowder. Being obliged to pass great part of the day in the open air during a cold and moist season, in order to render his experiments more decisive, his health, which was naturally delicate, became very much impaired. He partly recovered it, but again fell a victim to his thirst of knowledge; for he was at one time nearly destroyed by inspiring the oxygenated muriatic acid gas, which occasioned a convulsive asthma, that at times appeared to abate, but was found to be incurable. The assistance of art was insufficient to save him, and he died at Paris on the 21st of July 1797, of a pulmonary consumption, in the flower of his age, being only thirty-six.