418 



himself; the one being HCl + HAd (if Ad be the symbol of amido- 

 gene), while the other is HgCl + HgAd, so that the mercury in the 

 latter takes the place of the hydrogen in the former. 



It was, however, in the oxysalts, such as the sulphate of am- 

 monia, that the presence of an atom, or equivalent, of water, or 

 at least of the elements required for the composition of such an 

 equivalent, appears to have suggested to Berzelius the theory, that 

 what seemed to be hydrate of ammonia (NHj+HO) was really oxide 

 of ammonium (NH^ + 0). There are, undoubtedly, many tempta- 

 tions to adopt this view, besides the high reputation of its pro- 

 pounder. One is, that it assimilates the constitution of sulphate of 

 ammonia to what seems to be regarded by the greater number of 

 modern chemists, as the probable constitution of other sulphates, 

 nitrates, &c., for example, the sulphate of iron. When green 

 vitriol is to be formed by the action of sulphuric acid upon iron, 

 it is requisite to dilute the acid with water, before the action will 

 take place. The hydrogen of the water then bubbles oflF, but what 

 becomes of the oxygen which had been combined with it ? Does 

 it combine immediately, and as it were in the first instance, with 

 the iron, to form oxide of iron, on which the anhydrous sulphuric 

 acid may act, to produce sulphate of oxide of iron, according to 

 the view which seems, till lately, to have been adopted : or does 

 this oxygen, from the water, combine rather with the sulphuric 

 acid to produce a sort of oxide thereof, and does i\i\s sulphat-oxygen 

 act on the pure metallic iron to form with it a sidphat-oxide, as 

 many eminent chemists now appear to think? Whatever may 

 be the final judgment of those who are entitled to form opinions on 

 questions such as these, it cannot, I conceive, be justly said, that 

 the questions themselves are unimportant. They touch on points 

 connected with the philosophy of chemistry, are essentially con- 

 nected with its theory, and cannot always be without an influence 

 upon its practice. 



Now according to the Berzelian view of sulphate of ammonia, 

 that is the salt produced by the mutual action of sulphuric acid, 

 water, and ammonia, this salt is properly a sulphat-oxide of the 

 compound metal ammonium (NH,4-S0J, in the same way as green 

 vitriol, on the view last mentioned, is sulphat-oxide of iron 



