306 INFLAMMABLES. 



known to chemistry, have inflammable or metallic matter, as their 

 basis, and with only a few exceptions, it has been proved to be com- 

 bined with oxygen, which, instead of being regarded as the exclusive 

 acidifying principle, may still be viewed as sustaining this agency in 

 nearly all cases. 



Thirty years ago, there were three acids whose composition was 

 unknown, namely, the muriatic, the boracic, and the fluoric. Although 

 the latter is still undecomposed, the boracic acid has followed the 

 general analogy, having yielded a new combustible body, boron, united 

 to oxygen. The muriatic acid is now believed to be composed of hy- 

 drogen and chlorine. Sulphuretted hydrogen has most of the proper- 

 tes of an acid, but contains only sulphur and hydrogen ; the hydriodic 

 acid consists of iodine and hydrogen, and the prussic acid of carbon and 

 nitrogen, united to form a compound base, which is however not acid, 

 until it unites with hydrogen. Thus, there are four* acids in which 

 hydrogen appears to be essential to the acidity, and oxygen is not 

 present ; while the bases of three of these acids, namely, sulphur, io- 

 dine, and chlorine, form other acids, by uniting with oxygen ; and even 

 the compound basis of the prussic acid, consists of elements which, 

 individually, form acids with oxygen. 



Some chemists are now inclining to the opinion, that no one princi- 

 ple can be regarded as being endowed with the peculiar prerogative of 

 being an acidifier, but that acidity may, and often does arise from a 

 balanced or conjoined effect of several principles. f Oxygen exists, 

 as we have seen, in all the alkalies, except ammonia, and in all the 

 earths and metallic oxides, so that we cannot attribute to it the ex- 

 clusive property of producing either acidity or alkalinity, although it 

 is in most instances concerned in both ; still, that body without which 

 another would not be acid, must be considered as its acidifier. 



Most of the acids that have been discovered, are of very little im- 

 portance ; but several of the principal acids are eminently valuable, 

 and their history, being equally instructive and interesting, will be 

 developed with sufficient detail, in connexion with that of the in- 

 flammable bodies that form their bases. In giving the history of the 

 principal acids, I shall therefore pursue the synthetical course, as 

 being the most convenient and intelligible, although the analytical was, 

 for the same reasons, adopted in the account of the alkalies and 

 earths; or, in other words, the bases of the most important acids will 

 be presented first, whereas those of the fixed alkalies and earths 

 were presented last. 



* Besides others of a most doubtful character, as that composed of hydrogen and 

 tellurium. 



t For an ingenious discussion of this view, see Murray's Elements, 6th Ed. Vol. 

 II, Art. Acids. Mr. Murray is inclined to think that even the water, usually re- 

 garded as combined with acids and alkalies, acts rather by its element?, than in the 

 character of water, a fact which it m;iy be difficult either to prove or disprove. 



