60^ Chemical Experiments on Mercury, 



Of Phosphites. 



The phosphites likewise deoxvgenate the oxides of mer- 

 curv, but their action is incomparably less than that of the 

 phosphorous acid. It appears Lo be subordinate to the force 

 of affinity of the phosphorous acid with its base, and to 

 the action which this may equally exercise upon the oxides 

 of mercury : the phosphites therefore do not seem to us to 

 be capable, in any case, of afl'ording an accurate means for 

 the analysis of thesi? oxides. They also deoxvgenate the 

 mercurial salts ; but this action is weakened by the same 

 e.uises. 



Of the Action cf Phosphorus upon the Mercurial Oxides and 

 Salts. 



Pclleticrj who has attempted to combine phosphorus with 

 all the metals, says, that on treating the red oxide of mer- 

 cury with this substance by means of water, in a gentle 

 heat, he obtained a phosphuret of mercury in which the 

 phosphorus seems to exist in a state of feeble combina- 

 tion, and that he obtained by the same operation some 

 phosphoric acid. On repeating his experiment we obtained 

 the same results ; but it appears to us that the formation of 

 the phosphoric acid which is produced in it may be differ- 

 ently explained. We are of opinion that the phosphorus 

 (which gives origin to this acid) attracts a portion of oxy- 

 gen from the atmospheric air, and passes into the state of 

 phosphorous acid. What has led us to form this conclu- 

 sion is this: The phosphorus which is carried off by the va- 

 pours of the water burns at the surface of the latter; and 

 consequently forms there phosphorous acid, which must be 

 changed into phosphoric, in proportion as it seizes the 

 oxvc;en from the red oxide of mercury. This explanation 

 appears to us the more natural, as phosphorus, placed in 

 contact with the red oxide, does notbecomeaciditicd, though 

 it deoxygenates the latter, as we shall show hereafter, and 

 as phosphorus boiled in water is changed, by this simple 

 operation, into phosphorous acid. 



When phosphorus is placed in contact with red oxide 

 and water in the cold, it lirst attracts oxygen from the red 

 oxide, and reduces it lirst of all into gray oxide, and at 

 length to the metallic state; but in this case no phospho- 

 rous acid nor phosphoric acid is formed; the phosphorus 

 merely becomes oxidated, arid assumes a dark colour. It 

 is not difficult to conceive the theory of this phaanomenon : 

 the phosphorus, having great avidity for oxygen, separates 

 it from the oxide with which it is in contact ; but this 



couibuslion 



