%g% Om THE NATURE OF OXIMURIATIC ACID. 



Bothexp!ana- ^^^^ ^'^'^J appear an induction, which to apply to all the 

 tions hypothf- phenomena tarther requires some hypothetical assumptions. 

 Considerintj the experiment of the production of oximuriatic 

 acid, by distilHng muriatic acid from substances which im- 

 part oxigen, the mojit direct conclusion is, that it is a com- 

 pound of oxigen and muriatic acid, but to apply this m ex- 

 plaining the agencies of both acids, it is necessc ry to sup- 

 pose in some cases changes to occur: the formation or de- 

 composition of wnter for example, of which we have no in- 

 dependent proof. Considering on the other hand the txpe- 

 liment of the mutual action of oximuriatic and hidrogeu 

 gasses, the most direct inference is, that muriatic acid is a 

 compound of these substances; but in adopting this a* the 

 basis of a theory, it is equally necessary to advance suppo> 

 sitions, and in particular to suppose without any actual 

 proof, that in different cases water is formed or decomposed. 

 These suppositions are not always required in the two sys» 

 terns in relation to the same fact; but stili, wherever an hy- 

 pothesis is required in the one, a corresponding hypothesis 

 will be found necessary in some part of the other. They 

 occur on thq whoje just as frequently in Mr. Davy's system 

 as in the opposite one, and they areaslittle supported by ac- 

 tual proof. He, for example, has no better proof, that water 

 is formed when muriatic acid is distilled from black oxide of 

 manganese, than i have of its formation in the mutual ac- 

 tion of oximuriatic gas and hidrogen, or that it is decom- 

 posed when oximuriatic acid is ex|)osed to solar light, than 

 1 have of its decomposition when a metal is acted on by 

 muriatic acid gas. The two opinions are perfectly alike 

 %vith regard to the evidence on which they rest derived froi*. 

 the above facts; and to select in one of them that part where 

 the induction appears direct, and take it for granted that 

 is true, the hypothetical assumptions, which must be 

 farther made, necessarily follow : Uut to pursue the reverse 

 method with regard to the other, to represent it as an hypo- 

 thesis, by bringing forward the parts which require the as- 

 sumption of hypothesis, and neglect or reject the more di-r 

 rect induction, is a mere sophism. Ihis is exactly what Mr. 

 J* Davy does, no doubt without being aware of it, hiserrour 

 , arisiaff 



