5. Compounds of two incombustible principles. These are either earths with earths, as in (a) pottery, which for the most part is a mixture of aggregates ;— of earths with alkalies, which form (b) glass.
6. Compounds of a combustible and an incombustible principle. (a) Sulphurets of lime, magnesia, barytes, strontites, potash, sod.., ammonia ; (b) carburet of alumina; and (c) phosphurets of lime ; barytes ; strontites.
7. Compounds of two combustible principles. (a) Hydrogen with carbon ; carburetted hydrogen gas ; supercarbu retted hydrogen gas, or olefiant gas. (b) Hydrogen with metals ; gasiform sus pension of arsenic, zinc, or iron. (c) Car bon with sulphur ; carburet of sulphur.
(d) Carbon with iron ; carburet of iron, or crude iron. (e) Sulphur with hydro gen; suiphuretted hydrogen gas. (f) Sulphur with phosphorus ; sulphuret of phosphorus. (g) Sulphur with most of the metals; sulphurets of each. (h) Phos phorus with hydrogen ; phosphorized hy drogen gas;phosphuretted hydrogen gas.
(i) Phosphurets of carbon. (k) Phos phurets of many of the metals. (1) Me tals with metals ; alloys.
III. Secondary compowzds, or compounds of more than two simple principles.
Though it cannot yet be determined whether the binary and other corn. pounds, enumerated in the last section, may exist as distinct principles in the combination into which they may enter, it is nevertheless certain, that, either from this cause, or from the general pre dominance of the attractions to which they owe their formation, the appear ances in composition and decomposition are such as admit of the affirmative sup position in by far the greater number of cases. This was taken for granted by the earlier chemists, and habit and con venience has continued their language to the present time.
The binary compounds, taken in the preceding order, will indicate the follow ing secondary combinations.
1. Water combines with a great num ber of bodies, and in general maybe se parated by evaporation, congelation, or the effect of elective attraction, without any change in its own composition. It has been accordingly considered for a long time as a simple element, and is even now very often disregarded in its agency upon substances which it may hold in solution. (a) It absorbs very small portions of oxygen, hydrogen, or mote, and emits them upon raising the temperature, or lowering it to congela tion. No proof has been given of its be ing capable of uniting imperfect combi nation with either of its component parts beyond the point of saturation. (b) It dissolves barytes plentifully, and stron tites and lime sparingly ; and it very ac tively takes up large, proportions of the alkalies; but from all these it may be separated without alteration by mere heat. (c) Its action upon carbon, sul
phur, phosphorus, or the metals, is not sufficient to produce any sensible combi nation or decomposition, unless at a very elevated temperature, such as that of ig nition. (d) The oxides are scarcely af fected by it ; perhaps only when they ap proach the state of acidity. (e) Many of the acids unite strongly, and in all pro portions, with it, and they are all more or less soluble. (f) The sulphurets and phosphorets are suspended, and decom position of the water takes place by dis posing durable affinity, part of the sul phur taking oxygen from the water, and forming acid, which combines with the earth or alkali ; and another part of the combustible uniting with the hydrogen of the decomposed water, and forming hydrosulphuret, part of which remains in solution, and part rises in form of gas. (g) The compounds of two or more com bustibles are not sensibly acted upon by water.
2. The alkalies combine (a) with all the acids, and form compounds called neutral salts, more or less soluble in water ; and also (b) with several of the earths, and (c) of the metallic oxides ; forming combinations, which, from the little attention yet paid to them, have re ceived no particular denominations.
3. The earths also unite (a) with the acids, and form salts similar to those called neutral, and also for the most part soluble in water. Some of these likewise unite (6) with each other, and (c) with metallic oxides, by compound attraction during precipitation in the hu mid way.
4. Acids are the most powerful agents of combination with alkalies, earths, and metallic oxides, in the humid way, with which, as has been observed, they form salts. The earth silex is not taken up in any perceptible quantity by any acid but the flooric, and this suspends it even in the form of gas.
5. The compound of hydrogen and sulphur acts in the manner of an acid upon the alkalies, earths, and metallic oxides. For which, and the effect of acids on the compound combustibles, re• ference must be made to the respective articles.
It would carry us too far into the busi ness of arrangement in this place, if ,we were not to adopt the same proceeding of referring to the parts and products of VEGETABLE and ANIMAL bodies ; we shall therefore only mention five classes of the products of organized substances, which, from their exclusive application to chemical operations, cannot be passed without notice. These, in the last re sults, afford carbon and hydrogen, or carbon, hydrogen, and oxygen. They are, (a) alcohol, or spirit, ardent ; (6) ether ; (c) oils, volatile ; (d) oils, fixed ; (e) bitumens.