258 On the Nature of Muriatic Acid. [Oct. 



we calculate this result, we find that 72 parts of oxide of copper 

 contain 14*87 parts of oxygen, and that the quantity of oxygen 

 in 15 "9 parts of water is 14*32. Thus it appears that the oxygen 

 in the water, as in the subsulphate, is equal to the oxygen in the 

 oxide.* As we know that 100 part* of muriatic acid are neu- 

 tralized by 147*27 parts of oxide of copper, that is to say, that 

 the atom of acid is to the atom of oxide as 100 : 147*27, it 

 follows that the subsalt is composed of one atom of acid and four 

 atoms of hydrate of copper. Thus you see the admirable har- 

 mony that reigns in these compounds according to the old mode 

 of explaining their composition. 



Let us now consider the composition of this salt according to 

 the new hypothesis. Muriatic acid, according to this hypothesis, 

 is a compound of one atom of chlorine and one atom of hydro- 

 gen. Hence it follows that the submuriate contains 16*08 parts 

 of muriatic acid for 72 parts of oxide of copper. The water in 

 combination amounts only to 1 1 .92 parts : but as analysis gives 

 us 15 9, we must suppose the 3*98 of surplus formed by the 

 decomposition of the acid ; the hydrogen of which forms water 

 with part of the oxygen of the oxide ; at the same time that the 

 metal of the oxide combines with the chlorine evolved. In the 

 1 1 *92 parts of water admitted by the new hypothesis there are 

 only 10*74 of oxygen, that is to say, ^ths ot the quantity con- 

 tained in tlie oxide of copper. Hence the subsalt contains one 

 atom of oxide and f-thsof an atom of water; that is to say, that 

 the water is to the base in a ratio inconsistent with the doctrine 

 of definite proportions. Hence the explanation given by the 

 new hypothesis cannot be accurate. 



The submuriate of lead containing water (that is prepared by 

 precipitation) furnishes still a better proof, because the water 

 which it contains is more easily determined by direct experi- 

 ment ; but I chose the submuriate of copper in preference, 

 because, if you think proper to examine what I have said, you 

 may do it without any tedious experiment; you have only to 

 compare what I have said respecting the submuriate of copper 

 with the analysis of it published by Mr. John Davy in the Phil. 

 Trans, for 1812. 



If, on the other hand, we examine a submuriate without 

 water of combination, as the submuriate of lead exposed to a 

 red heat, we shall find that according to the old hypothesis the 

 acid is united to one atom of oxide: while according to the new 

 hvpothesis these submuriates constitute a perfectly new class of 

 bodies, composed of chlorine, metal, and a proportion of oxygen 



* If we calculate by the table given in (he Annals of Philosophy, vol. ii. 

 p. 32, we shall find that the oxygen in 72 parti of peroxide of copper amounts 

 to 14'4; and the oxvj;en in IS'9 parts of water is 14-05. But these changes 

 do not destroy the identity observed by Berzelius. — T. 



