1813.] On the. Nature of Muriatic Add. 259 



insufficient for the oxidation of that metal. The new hypothesis 

 represents the composition of the submuriates destitute of water 

 by one atom of chlorine, one atom of metal, and three atoms 

 of oxide. I suppose the defenders of the new opinion will 

 endeavour toreconcileit with the doctrineof definite proportions, 

 by pretending that the submuriates with water are composed of 

 one atom of cuprane (for example) and three atoms of hydrate 

 of copper : but if such an allegation is made, we shall have a 

 right to reproach them with seeking rather to defend an hypo- 

 thesis at all hazards than to discover the truth. 



The want of agreement between the new theory and the doc- 

 trine of definite proportions is such, that lam surprized it could 

 ever gain credit. The muriate, nitrate, and sulphate of am- 

 monia, possess analogous properties, and are all classed among 

 ammoniacal salts. We find the same analogy among the 

 compounds of potasli with the same acids, and of course are 

 disposed to class them all among the salts. But according to 

 the new hypothesis, a muriate of potash cannot exist ; and what 

 was formerly considered as a salt contains, notwithstanding its 

 exact analogy with the salts, neither an acid, nor oxj'gen, nor 

 even potash itself. The new hypothesis admits a muriate of 

 ammonia merely because we know no method of obtaining that 

 salt free from water : but the same thing holds Avith the sulphate 

 and nitrate of ammonia, and with almost all the ammoniacal 

 salts ; for boracic acid and arsenious acid, deprived of water, are. 

 not capable of absorbing the smallest portion of dry ammoniacal 

 gas. 



Let us attend to the muriate of iron formal by exposing iron 

 to an excess of oxymuriatic acid. It is red, the colour of the 

 oxide passing, as it were, through that of the acid with which it 

 is in combination ; yet according to the new hypothesis this body 

 contains no oxygen. The compound formed by the action of 

 light on a mixture of oxymuriatic acid and oxide of carbon, to 

 which a name has been given of unlucky omen for the science, 

 affords a fine illustration of the doctrine of chemical proportions, 

 according to which bodies possessing the same electro-chemical 

 modifications combine in such proportions that they contain 

 equal quantities of oxygen. The old hypothesis considers it as 

 composed of an atom of muriatic acid and an atom of carbonic 

 ■m'k\, and consequently as analogous to the fluoboracic acid: 

 while, according to the new hypothesis, it is composed of car- 

 bon and of two electro-negative bodies, chlorine and oxygen; that 

 is, of one radicle and two (to use the expression) oxygens. 



But I conceive what I have said to he sufficient to enable vou 

 U> judge which of the two hypotheses explains the phenomena 

 in the most plausible and satisfactory manner. 



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