ON THE WATER IN MURIATE OF AMMONIA. ]C)7 



had supposed the question, whether this doctrine is a 

 theory or an hypothesis, to have been brought into that 

 point of view, that it was too obvious to bear any farther 

 discussion. I may be mistaken in this; but still I cannot 

 persuade myself, that there is any necessity for my entering 

 on any recapitulation ov extension of the arguments I have 

 employed. With many of your readers they may have 

 more weight than with my opponents; and my want of 

 success in the latter respect, it is possible, may be owing 

 not so much to deficiency in the argument, as in the per- 

 son to whom it is addressed; for one who, like Mr. J. 

 Davy, cou^ld not distinguish between an inference from a 

 fact, and the expression of the fact itself*; who could 

 confound an insulated fact, which his hypothesis did not 

 explain, with an ultimate fact of which no explanation was 

 to be expected, and who could call this fact one of the 

 axioms of the sciencef; can hardly be expected, even with 

 the most candid dispositions, to discriminate very accurately 

 between the nicer limits, by which theory and hypothesis 

 are defined. [ shall not attempt therefore to convince this 

 gentleman, but shall leave him in full possession of the 

 belief (if he seriously entertains it) that he has answered all 

 my arguments, refuted all my experiments, and established 

 his brother's opinion as a genuine theory. 



I shall only add, that the late progress of chemical Relation <*f 



discovery has shown, that there is nothing; peculiar in the rnur,aUc ac ** 



J i to w.i ter not 



relation of muriatic acid to water, such as is maintained peculiar. 



in the common doctrine. The able researches of Gay- 

 Lussac and Thenard and of Berthollet have shown, that 

 all the more powerful acids, the sulphuric, nitric, phos- 

 phoric, and fluoric, contain combined water, from which 

 they cannot be obtained free in an insulated state. Those 

 of your readers, who feel an interest on this subject, will 

 find a summary of these researches in the supplement to the 

 second edition of my System of Chemistry, lately published. 

 I have the honour to be, 



Your most obedient servant, 

 Edinburgh, May 21, 1812. JOHN MURRAY. 



* Journal, vol. XXIX, pp. 39, 195. 

 $ Ibid, vol. XXVIIi, pp. 199, 302. 



