The Terminology of Mineralogy being thus reformed, an attempt was made to improve its Nomenclature also, by following the example of Botany. Professor Mohs was the proposer of this innovation. The names framed by him were, however, not composed of two but of three elements, designating respectively the Species, the Genus, and the Order[15\4]: thus he has such species as {275} _Rhombohedral Lime Haloide_, _Octahedral Fluor Haloide_, _Prismatic Hal Baryte_. These names have not been generally adopted; nor is it likely that any names constructed on such a scheme will find acceptance among mineralogists, till the higher divisions of the system are found to have some definite character. We see no real mineralogical significance in Mohs's Genera and Orders, and hence we do not expect them to retain a permanent place in the science. [Note 15\4: _Hist. Ind. Sc._ b. xv. c. ix.] The only systematic names which have hitherto been generally admitted in Mineralogy, are those expressing the chemical constitution of the substance; and these belong to a system of technical terms different from any we have yet spoken of, namely to terms formed by systematic modification. III. The language of Chemistry was already, as we have seen, tending to assume a systematic character, even under the reign of the phlogiston theory. But when oxygen succeeded to the throne, it very fortunately happened that its supporters had the courage and the foresight to undertake a completely new and systematic recoinage of the terms belonging to the science. The new nomenclature was constructed upon a principle hitherto hardly applied in science, but eminently commodious and fertile; namely, the principle of indicating a modification of relations of elements, by a change in the termination of the word. Thus the new chemical school spoke of sulph_uric_ and sulph_urous_ acids; of sulph_ates_ and sulph_ites_ of bases; and of sulph_urets_ of metals; and in like manner, of phos_phoric_ and phos_phorous_ acids, of phos_phates_, phos_phites_, phos_phurets_. In this manner a nomenclature was produced, in which the very name of a substance indicated at once its constitution and place in the system.