[181] There is a French translation of this work, entitled “Litheognosie, ou Examen Chymique des Pierres et des Terres en général, et du Talc de la Topaz, et de la Steatite en particulier; avec une Dissertation sur le Feu et sur la Lumière.” Paris, 1753. With a continuation, constituting a second volume, in which all the experiments in the first volume are exhibited in the form of tables. His different chemical works (his Lithogeognosia excepted) were collected and translated into French by M. Demachy, in the year 1759, and published in four small octavo volumes. The chemical papers contained in these volumes are thirty-two in number. Some of these papers cannot but appear somewhat extraordinary to a modern chemist: for example, M. Duhamel had published in the memoirs of the French Academy, in the year 1737, a set of experiments on common salt, from which he deduced that its basis was a fixed alkali, which possessed properties different from those of potash, and which of course required to be distinguished by a peculiar name. It is sufficiently known that the term _soda_ was afterwards applied to this alkali; by which name it is known at present. Pott, in a very elaborate and long dissertation on the base of common salt, endeavours to refute these opinions of Duhamel. The subject was afterwards taken up by Margraaf, who demonstrated, by decisive experiments, that the base of common salt is _soda_; and that soda differs essentially in its properties from potash. Pott’s dissertation on _bismuth_ is of considerable value. He collects in it the statements and opinions of all preceding writers on this metal, and describes its properties with considerable accuracy and minuteness. The same observations apply to his dissertation on zinc.