Fire-alkali Ammonia Vegetable, and Animal alkalies. Air-alkali Potash Alcaloids Alcaloids. Water Soda Urea. Earth Lithium Bile, &c. Salt Inflammable Ore-alkali 514. The earths proper do not consist of two principles, and do not, therefore admit of being chemically divided. 515. This division is only incorrect in a naturo-historical sense, because it has no reference to the totality. Inasmuch as every mineral class is viewed as having originated out of only one or two elements, it divides by the chemical method only into constituent parts or fractions, as the acids and alkalies, which are obviously only moieties, and taken in a strict sense are not true minerals. b. _Genetic Division of the Classes._ 516. The total division only is genetic and consequently correct. 517. As the classes have originated through that which directly preceded them, namely, the elements; so must the divisions of the classes be determined by the other classes. Such divisions are called orders. Every class necessarily divides into four orders. Order 1. Earths. 2. Salts. 3. Inflammables. 4. Ores. _CLASS I._ EARTHS. 518. There must be therefore pure earths, haloid or salt-earths, inflammable earths and metallic earths or ores. 1. The Earth-earths must have neither saline, nor inflammable nor metallic properties, and thus also be insoluble in acids. Such is the case with the _Silicious earths_. 2. The Haloid-earths must have saline properties, dissolve in acids, but not fall to pieces when exposed to air and fire. Such is the behaviour of _Argillaceous earth_; it admits besides of combining with water, that antetype of the salts. 3. The Inflammable earths must be soluble in acids and exhibit electric or aerial properties. Such is the behaviour of the _Talcose earths_; its minerals are unctuous, fall when exposed to the air into electric lamellæ, and burn brittle. 4. The Metallic earths must undergo change in acids, air and fire. The _calcareous earth_ dissolves in all acids, burns corrosive and becomes almost a metallic calx. The Orders of earth are consequently: 1. Earth-earths _Silica_; Quartz, &c. 2. Haloid-earths _Clays_; Felspar, &c. 3. Inflammable-earths _Talcs_; Mica, &c. 4. Metallic-earths or Ores _Calx_. 519. Nature does not produce any so-called pure calcareous earth, but only this earth in an _oxydated_ condition. Carbonic acid is the oxygen of the earth that has become free, and the corroding calx is the Metallic, the other constituent part of the Earthy, which has obtained some oxygen, but lost the Aqueous by the carbonic acid and thereby has become corrosive.