Dr. Thomson on Oxalic Acid. 
89 
We may now examine the decomposition which takes 
place when oxalate of lime is exposed to heat. Let an atom of 
oxygen be zv, an atom of carbon c, and an atom of hydrogen h. 
An integrant particle of oxalic acid may be represented 
by 4 w -f 3 c + 2 h. We may represent the composition and * 
weight of an integrant particle of each of the substances into 
which oxalic acid is decomposed by heat, by the following 
symbols and numbers : 
Carbonic acid 
2 zv -f c weight 
I6.5 
Carbureted hydrogen 
c -{- 2 h 
- 
6.5 
Carbonic oxide 
ZV c 
- 
IO.5 
Water 
zv -f- h 
- 
7 
Charcoal 
c 
4.5 
We may now conceive 3 
particles of oxalic acid 
to be 
decomposed at once, and to 
resolve themselves into 
these 
substances, in the following proportions : 
4 particles of carbonic acid 
= 
8 zv 
+ 4 < c 
2 particles of carbureted hydrogen = 
- 
- 2 c 
+ 4 ^ 
2 particles of carbonic oxide 
= 
2 zv 
+ 2 c 
2 particles of water 
= 
2 ZV 
- - 
+ 2 h 
1 particle of charcoal 
= 
- 
1 c 
Total 
12 ZV 
+ 9 C 
+ 6 h 
3 particles of oxalic acid 
= 
12 ZV 
+ 9 c 
+ 6 k 
We see that such a decomposition is possible. It remains 
only therefore to see whether the weights of these substances, 
which result from this hypothesis, correspond with the pre^ 
ceding analysis. Now, 
mdcccviii. 
N 
