I have reason to believe that the laborious part of this translation and compilation was made by Mr. Chicholm, whom Dr. Lewis employed as his assistant. Mr. Chicholm, when a young man, went to London from Aberdeen, where he had studied at the university, and acquired a competent knowledge of Greek and Latin, but no means of supporting himself. On his arrival in London, one of the first things that struck his attention was a Greek book, placed open against the pane of a bookseller’s window. Chicholm went up to the window, at which he continued standing till he had perused the whole Greek page thus exposed to his view. Dr. Lewis happened to be in the shop: he had been looking out for a young man whom he could employ to take charge of his laboratory, and manage his processes, and who should possess sufficient intelligence to read chemical works for him, and collect out of each whatever deserved to be known, either from its novelty or ingenuity. The appearance and manners of Chicholm struck him, and made him think of him as a man likely to answer the purposes which he had in view. He called him into the shop, and after some conversation with him, took him home, and kept him all his life as his assistant and operator. Chicholm was a laborious and painstaking man, and by continually working in Lewis’s laboratory, soon acquired a competent knowledge of chemistry. He compiled several manuscript volumes, partly consisting of his own experiments, and partly of collections from other authors. At Dr. Lewis’s death, all his books were sold by auction, and these manuscript volumes among the rest. They were purchased by Mr. Wedgewood, senior, who at the same time took Mr. Chicholm into his service, and gave him the charge of his own laboratory. It was Mr. Chicholm that was the constructor of the well-known piece of apparatus known by the name of Wedgewood’s pyrometer. After his death the instrument continued still to be constructed for some time; but so many complaints were made of the unequal contraction of the pieces, that Mr. Wedgewood, junior, who had succeeded to the pottery in consequence of the death of his father, put an end to the manufacture of them altogether.