"From this epocha the hypothesis of the tria prima seems wholly to have been abandoned: whilst a very different doctrine was proposed by Beccher in his Physica Subterranea [1669], and to which we are perhaps indebted for the present advanced state of chemical science; since he was the first to point out chemical analysis as the only true method of ascertaining the elements of bodies. According to his doctrine, all terrestrial bodies are composed of water, air, and three earths; viz. the fusible, the inflammable or sulphureous, and the mercurial. The three earths, combined in nearly equal proportions, compose the metals: when the proportion of mercurial earth is very small, they compose stones; when the fusible predominates, the resulting compounds are the precious stones; when the sulphureous predominates, and the fusible is deficient, the compounds are the calorific earths: fusible earth and water compose an universal acid, very much resembling sulphuric acid, from which all other acids derive their acidity; water, fusible earth, and mercurial earth, constitute common salt; sulphureous earth and the universal acid form sulphur. Such was the theory of Beccher, which was afterward considerably modified by Stahl."