OF SOME SALTS OF SODA. 81 
drous carbonate of soda is capable of absorbing, 
I, on the 20th October, 1835, put 47.4 grains=1 
atom, (supposing the atom of soda to be 28, and 
that of carbonic acid 19.4) prepared by calcin- 
ing the’ bi-carbonate, into a watch glass’ of 
known weight, and left it exposed to the atmos- 
phere in a room in which no fire was kept. By 
frequently weighing the glass and contents I 
found the gain of weight to be as follows. 
| Oct. |Weight gained| Oct. |Weight gained. 
21 3.3 grains. 27 18.6 grains. 
———EE 
22 6.1 28 21.1 —— 
23 9.1 —— 29 23.6 —— 
24 11.8 —— 30 26.6 —— 
25 13.8 —— 31 28.6 —— 
26 16.1 —— 
The salt having concreted into a rather hard 
mass was now broken up, so that it might the 
more readily acquire more moisture. 
Nov. |Weight gained.]| Nov. |Weight gained. 
1 31.6 grains. 3 38.6 grains. 
2 34.1 4, 40.8 
The salt was now removed from the watch 
glass, crushed, and spread over the surface of 
a dinner plate, so that the process might be 
sooner finished. 
