54 Oji the Cause of Cheinical Proportion^. [Jan. 



other body except oxygen, we are able, however, from the laws of 

 chemical proportions, to determine the weight of its volume : for 

 if we compare the ditferent degrees of oxidation of muriatic acid 

 with the composition of the muiiates, we find that muriatic acid 

 must be M + 2 O. If, according to one of my experiments 

 (Ann. de Chim. Aug. 1811, p. 153), 100 parts of silver unite 

 with 7"44 parts of oxygen; and if 100 parts of muriate of silver 

 be composed of 19*0J5 of muriatic acid and 80'9(}5 of oxide of 

 silver, then the volume of muriatic radicle will weigh 139 5G : but, 

 on account of our ignorance of the true weight of a volume of 

 sulphur, it is possible that 100 parts of silver, when oxidated, absorb 

 only 7'^<^ parts of oxygen. In that case the muriate of silver will 

 contain 19 091 of muriatic acid, and the volume of muriatic radicle 

 will weigh as much as \G2'2. From this it is obvious how very 

 accurately the muriate must be analyzed to obtain a result by cal- 

 culation which may be depended on. It follows from the determi- 

 nation which I have just stated, that the degrees of oxidation of the 

 muriatic radicle at present known, are, muriatic acid, M + 1^ O j 

 oxymuriatic gas [hyperoxydum miiriatosum), JM + 3 O; euchlorine 

 gas {hyperoxydum murkilJaan), M + 4 O ; oxymuriatic acid, 

 M + S O. Is there a combination M -f 6 O? and is it an oxy- 

 murlalous acid ? We know that a solution of caustic potash im- 

 pregnated with oxymuriatic gas has very difterent properties from 

 those of a solution of hyper-osymuriate of potash^ Does it owe its 

 peculiar properties, as those of bleaching, to the presence of au 

 hypcr-oxymuriate of potash which is decomposed into muriate and 

 oxymuriate by the act of crystallization ? 



3. Phosphoricuin, phosphorus (P). — In an analysis of phosphate 

 of lead (Ann. de Chim. Oct. 1811, p. fj) 1 found that 100 parts of 

 phosphoric acid are neutralized by 380'5G parts of oxide of jead. 

 M. Rose found that 100 parts of phosphorus absorb, in order to be 

 converted into an acid. 111 parts of oxygen. This proves that the 

 100 parts of phosphoric acid cannot contain more than two times 

 as much oxygen as the bases which neutralize it. If we consider 

 that tlie analysis of tlie phosphate of lead is susceptible of greater 

 exactness than an expeiiment to unite the constituents of the acid 

 can be, it will follow that a volume of phosphorus ought to weigh 

 167'512. If we make the same calculation from my analysis of 

 the phosphate of barytes, we obtain for the volume of phosphorus 

 167 3. This determination is founded on the supposition that 

 phosphoric acid is P + 2 O. At the same time it must be allowed 

 to be unlikely that phosphorous acid should contain only a single 

 volume of oxygen. Davy establishes (Elements of Chemical Phi- 

 losophy, p. 209,) that phosphorus in phosphorous acid is combined 

 with half the quantity of oxygen with which it is combined in 

 phosphoric acid. But as he found that iOO parts of phosphorus, in 

 order to becorne phosphorous acid, absorb 77 P^rts of oxygen, one 

 would be rather disposed to conclude that the oxygen in phosphorous 

 acid is to that in phosphoric acid as 2 : 3. I have never made any 



