86 * 
Dr. Thomson on Oxalic Acid. 
numbers. For example, the numbers which correspond to 
the four elements, oxygen, azote, carbon, and hydrogen, are 
the following : 
Oxygen 6 
Azote - 5 
Carbon - 4.5 
Hydrogen 1 
Now, in all compounds consisting of these ingredients, the 
proportion of the different constituents may always be repre- 
sented by these numbers,, or by multiples of them ; thus, the 
composition of the following substances may be thus stated. 
Oxygen. 
Hydrogen. 
Carbon. 
Azote. 
Water 
6 
+ 1 
Carbonic oxide - 
6 
+ 4 -5 
Carbonic acid 
2 x 6 
- 
+ 4-5 
Carbureted hydrogen 
- 
2X1 
+ 4-5 
Olefiant gas 
- 
1 
+ 4-5 
Nitrous gas - 
6 
- 
- 
+ 5 
Nitric acid 
2x6 
- 
- 
+ 5 
Nitrous oxide 
6 
- 
_ 
+ 2x5 
From the knowledge of this curious law, it is difficult to 
avoid concluding that each of these elements consist of atoms 
of determinate weight, which combine according to certain 
fixed proportions, and that the numbers above given, repre- 
sent the relative weights of these atoms respectively. Thus, 
an atom of oxygen weighs six, an atom of hydrogen one, 
&c. Water is composed of one atom of oxygen, and one atom 
of hydrogen ; carbonic acid of two atoms of oxygen, and one 
of carbon, &c. This curious theory, which promises to throw 
