1. His first paper, entitled "On the Aerial Acid," that is, _carbonic acid_, was published in 1774. In it he gives the properties of this substance in considerable detail, shows that it possesses acid qualities, and that it is capable of combining with the bases, and forming salts. What is very extraordinary, in giving an account of carbonate of lime and carbonate of magnesia, he never mentions the name of Dr. Black; though it is very unlikely that a controversy, which had for years occupied the attention of chemists, should have been unknown to him. Mr. Cavendish's name never once appears in the whole paper; though that philosopher had preceded him by seven or eight years. He informs us, that he had made known his opinions respecting the nature of this substance, to various foreign correspondents, among others to Dr. Priestley, as early as the year 1770, and that Dr. Priestley had mentioned his views on the subject, in a paper inserted in the Philosophical Transactions for 1772. Bergman found the specific gravity of carbonic acid gas rather higher than 1·5, that of air being 1. His result is not far from the truth. He obtained his gas, by mixing calcareous spar with dilute sulphuric acid. He shows that this gas has a sour taste, that it reddens the infusion of litmus, and that it combines with bases. He gives figures of the apparatus which he used. This apparatus demands attention. Though far inferior to the contrivances of Priestley, it answered pretty well, enabling him to collect the gas, and examine its properties. It is unnecessary to enter into any further details respecting this paper. Whoever will take the trouble to compare it with Cavendish's paper on the same subject, will find that he had been anticipated by that philosopher in a great many of his most important facts. Under these circumstances, I consider as singular his not taking any notice of Cavendish's previous labours.