42 On the Daltonian Theory of [July, 



the same numbers. The following table is submitted to the 

 chemical world as more convenient than the methods hitherto 

 followed ; and as the means employed in determining the num- 

 bers is every where stated, it were to be wished that they were 

 adopted by chemists in general, as far as they are accurate. If 

 the same numbers wen- ste.dily employed by all persons, they 

 would soon he recollected by chemists, who would thus be able 

 to state ihe composition of every compound without being 

 obliged to pefer to a book. The utility of such a recollection to 

 the practical chemist is too obvious to be pointed out. 



Weight of :in atom. 



1. Oxygen 1-000 



2. Hydrogen 0132 



3. Carbon 0'75 1 a 



4. Azote 0-878 b 



5. Phosphorus 1-320 c 



a This is obtained from carbonic acid, which I conceive, with 

 Dalton, to be a compound of 2 atoms of oxygen and 1 atom of 

 carbon. When charcoal is burned in oxygen gas, the bulk of 

 the gas is not altered, it is merely changed into carbonic acid. 

 Hence if from the weight of 100 cubic inches of carbonic acid 

 gas = 46*313 grains, we subtract the weight of 100 cubic 

 inches of oxygen gas = 33*6/2 grains, the remainder = 12*641 

 grains gives us the weight of carbon in 100 cubic inches of 

 carbonic acid gas. This shows us that carbonic acid is composed 

 of 27 i9 parts of carbon and 72'71 of oxygen. My analysis of 

 defiant gas gives 0*748 for the weight of an atom of carbon, 

 which comes very near the preceding. 



b This number is obtained from nitrous gas, which, I think, 

 Mr. Dalton has successfully shown to be a compound of 1 atom 

 azote and 1 atom oxygen ; and Gay-Lussac has proved it to be 

 a compound of equal measures of azotic gas and oxygen gas. 

 The number adopted by Sir H. Davy to represent an atom of 

 azote when reduced to our proportions would be 0"860, and that 

 of Mr. Dalton 0714. Ammonia gives us a different ratio if we 

 suppose it, with Dalton, to be a compound of 1 atom of 

 hydrogen and 1 atom of azote. The weight of an atom of azote 

 in that case would be 0*534 ; but if we consider ammonia as 

 composed of 2 atoms of hydrogen and 1 atom of azote, then the 

 weight of an atom of azote comes out 0*S76. Hence I conceive 

 ammonia to be a ternary compound. 



c This number is deduced from phosphoric acid. Sir H. 

 Davy has ascertained that the quantity of oxygen in phosphoric 

 acid is double of that in phosphorous acid. Hence, 1 think, 



