Dr. Thomson on Oxalic Acid. 
8 7 
an unexpected light on the obscurest parts of chemistry, 
belongs to Mr. Dalton. I have elsewhere illustrated it at 
considerable length.* 
The same law holds with respect to the salts. The acid 
and bases always combine in determinate proportions. We 
may affix numbers to all the acids and bases, which numbers, 
or their multiples, will represent all the combinations into 
which these bodies enter. Some of these numbers are given 
in the following table : 
Sulphuric acid 
33 
Barytes 
67 
Muriatic acid 
18 
Soda 
24 
Carbonic acid 
16.5 
Lime 
23 
Nitric acid 
17 
Ammonia 
6‘ 
These numbers may be conceived to represent the relative 
weights of an integrant particle of each of these substances ; 
formed on the supposition that an atom of hydrogen weighs 1 . 
It follows equally from this law, that the acids and bases com- 
bine particle with particle, or a certain determinate number 
of particles of the one with a particle of the other. 
One of the most important points in the investigation of 
compound bodies, is to ascertain the number which denotes 
the weight of an integrant particle of each of them, that of an 
atom of hydrogen being 1 ; because this number, or a mul- 
tiple of it, represents the weight of each, which enters into all 
combinations ; and because it enables us to estimate the number 
of elementary atoms of which eachis composed. From a careful 
comparison of the table of oxalates, given in a preceding part 
of this paper, with the weight of the different bases already 
* See System of Chemistty, III. 424, &c. 3d Edition. 
