on ihe Comh'inatioji^ nf Phosphoms ic'ilk Oxygen. 2/3 



phites are nearly the same with those of which we have spukcu 

 in treating of the hvpopiiospiiites. 



I liave analysed piiosphoroiis acid, of which Sir PI. Davy had 

 already given the proportions, to ascertain how niiich of chlore 

 the phosphorus absorbs in order to pass to the state of chlorure 

 at the minimum. My results do not differ sensibly from his. I 

 have found bv this means that the pho'^phorous acid is formed 

 of 'Phosphorus .. .57-18—100 



Oxygen .. .. 42-82— 74-88 



100 



Hence it follows that the oxvgen of the hypophospPiorous acid 

 is to that of the phosphorous acid as 1:2. 



The acid produced hv the slow combustion of the phosphorus 

 in the air, to which several phtenomena may be referred, is ne- 

 vertheless very little known. It differs from the foregoing not 

 only by its proportions, but also by its nature. It is not com- 

 bined in the wav it is with the oxides. The salts which have 

 been described heretofore by the appellation of phosphites are 

 not peculiar salts ; they are either phosphates, or more fre- 

 tjuently a mixture of phosphates and phosphites. 



Ought we to consider this substance as a simple mixture of 

 phosphoric and phosphorous acids ? Sir H. Daw merely makes 

 this assertion, but without anv proofs. I do not think, however, 

 that we can admit this idea ; — for, why should the conversion of 

 the phosphorous acid into phosplioric acid stop at a certain 

 ])oint of time ? — wherefore should we find constantly in this 

 substance the same proportions of oxygen and phosphorus ? If 

 its formation took place in a rapid manner, we might con- 

 clude that some particles of j)hosphorous acid escaped the com- 

 bustion ; but the tediousness of the process of obtaining it ex- 

 dudes all idea of an incom])lete combination. 



We might also suppose that the oxvgen of this .acid, forming 

 a binary combination with the phosphorus, is unequally divided 

 between two parts of the radical by the action of the bases, and 

 that there would result from this division phosphorous acid and 

 ))hos|)horic acid : but it seems much more probable that these 

 acids, even before the action of the oxides, are already com- 

 pletely formed and combined with each other, like the elements 

 of a salt. It is by adopting tliis last opinion that I intend to 

 call it phosplifilic acid; an appellation which reminds us thai 

 lliis acid has some analogy with the phosphates in its mode of 

 coni|)osition. 



M. Theuard has found by direct menns that the phosphatic 

 acid ought to he formcfl of 100 jiarts of phosphorus and 110-4 

 oNvgen, I ol)tained IOf> bv a different ujcthod. Neither of 



Vol.48. No. 222. Ocl. Ib'lC). JS these 



