CHEMISTRY. 



most part is a mixture of aggregates ; 

 of earths with alkalies, which form (6) 

 glass. 



6. Compounds of a combustible and an 

 incombustible principle, (a) Sulphurets 

 of lime, magnesia, barytes, strontites, 

 potash, sod-, ammonia; (6) 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 defiant gas. (6) 

 Hydrogen with metals ; gasiform sus- 

 pension of arsenic, zinc, or iron, (c) Car- 

 bon with sulphur; carburet of sulphur, 

 (rf) Carbon with iron ; carburet of iron, 

 or crude iron, (e) Sulphur with hydro- 

 gen; sulphuretted hydrogen gas. (/) 

 Sulphur with phosphorus ; sulphuret of 

 phosphorus. (#) Sulphur with most of the 

 metals; sulphwrets of each. (A) Phos- 

 phorus with hydrogen ; phosphorized hy- 

 drogen gas, phosphuretted hydrogen gas. 

 () Phosphurets of carbon, (fc) Phos- 

 phurets of many of the metals. (/) Me- 

 tals with metals ; alloys. 



III. Secondary compoiquls, or c,omp.ounds 

 of morp than two simple principles. 



Though it cannot yet be determined 

 whether the binary and other com- 

 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 

 azote, 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 in perfect 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 Iarge 4 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. (</) 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. (/) 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, pajt of which remains in 

 solution, and part rises in form of gas. 

 (j-) 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 (6) 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 fluoric, and this suspends it even iiv 

 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 



j^s^^^: 



