502 •*» THE NATOllK OF^OXIMURIATIC ACID. 



anomaly in comparison with its other supposed combioa- 

 tions. 

 WaoBtofac- To the explanotion I bad given of the want of Jiction 



SttcoaTand ^^^^^^'^ charcoal and oxirauriatic acid, that it is owing 

 03UBQuriauc partly to lli€ absence of the water required in the consti- 

 •***• tution of muriatic acid gas, and partly to the absence of that 



disposing affinity exerted by the acid in establishing other 

 combinations, Mr. Davy replies, that it would be less unob- 

 jectionable were it less hypothetical; that I do not prove mu- 

 liatic and carbonic gasses contain water, I only suppose it— 

 To this mistake that the one opinion is a theory, the other an 

 hypothesis, I have been forced to recur so often, that it is 

 scarcely necessary to point it out. Both are hypotheses, 

 and if I can explain a fact by the principle of the one, which 

 admits of po explanation by the principle of the other, the 

 •uperiority of the former is with regard to this point suffi- 

 ciently established— Besides, the application of the doctrine 

 «f disposing affinity alone affords an explanation of this 

 fact. I coufcidcr it therefore a& still giving a superiority to 

 the common system, for nothing can appear more anoma- 

 lous than that of all irjflararaable and nietaHic substances 

 Bone but charcoal remains unchanged by oximuriatic acid, 

 and nothing can be more satisfactory than to have a caus-.c 

 assigned for this. Mr. Davy considers it as of little im- 

 portance, though it is this apparent anomaly, and the sup- 

 posed difficulty of accounting for it according to the old 

 opinion, which gave rise to the new doctrine, or at least first 

 suggested the suspicion, that oximuriatic acid does not con- 

 tain oxigen; he is satisfied with the observation, that we 

 have no right to expect from a theory the explanation of h1- 

 timate facts; that is, not of corapreh«nsive facts arrived at 

 by a generalization which cannot be carried farther, for the 

 fact in question is not of this kind, but of individual facts 

 tirhich the theory will not explain; a very safe conclusion, in 

 which it may be proper for him to abide. This, he adds, is an 

 "ultimate fact, "one of tho^e which constitute as it were the 

 axiorosof the science;" and he adds, that he is glad it is not 

 tortured by hypothetical explanation. How it is elevated to 

 an axiom, taking this word in its common sense of a funda- 

 9i€utal proposition, stlf-evidentyand therefore not admitiiivg 



of 



