1813.] Definite Proportions in Chemical Combinations. 43 



Weight of an atom. 



6. Sulphur 2-000 



7. Boron 



Number of Weight of a 



atoms. particle. 



S. Water, composed of ... 1 o + I h 1*132 d 



9. Carbonic oxide 1 o + 1 c 1*751 e 



10. Carbonic acid 2 o + 1 c 2*751 



11. Nitrous gas r 1 o + 1 a 1*878 



it follows, that phosphoric acid is a compound of 1 atom of 

 phosphorus and 2 atoms of oxygen. Farther, it has been ascer- 

 tained that when phosphorus is burnt in oxygen gas each grain 

 of phosphorus absorbs 4± cubic inches of oxygen. Therefore 

 phosphoric acid is composed of 100 phosphorus and 151*52 of 

 oxygen, and phosphorous acid of 100 phosphorus and 7576 of 

 oxygen : and an atom of oxygen is to an atom of phosphorus as 

 75*76 to 100, or as 1 to 1*320 nearly. 



d I conceive water to be a binary compound. The opinion 

 advanced by Sir H. Davy, that it is a ternary compound of an 

 atom of oxygen united to 2 atoms of hydrogen, cannot, I think, 

 be supported. 



r It has been ascertained by accurate experiments that 100 

 measures of carbonic oxide for complete combustion require 50 

 measures of oxygen gas, and that the residue is 100 measures of 

 carbonic acid gas. Hence it follows that the quantity of oxygen 

 in carbonic acid is just double what exists in carbonic oxide, 

 while the quantity of carbon in both is the same. Berthollet's 

 objections to this conclusion are inadmissible. He seems, indeed, 

 to have given up the point himself. 



The determination of the compounds into which azote and 

 oxygen enter is attended with considerable difficulty. The reason 

 for considering nitrous gas as a binary compound, and its ana- 

 lysis, have been stated before. 1 consider it as exactly deter- 

 mined. The reasons assigned by Dalton for considering nitrous 

 oxide as a compound of 2 atoms of azote and 1 atom of oxygen, 

 seem to roe ((inclusive; and Gay-Lussac has shown that it 

 COn1 i ins just twice as much azoic as nitrous gas, supposing the 

 en in both the same. Hence its composition most be aa 

 stated in the table. The acid analysed 1 by Cavendish and Davy, 

 Rtw called nitric acid, 1 conceive to have been in fact nitrous 

 and. \\\y.<{ Mr. Dalton calls oxy-nitrie acid is true colourless 

 nitric acid, which Beems only to exisl in combination with water 



or i base. This I infer from the recant experiments of Chevreul 



