86 EFFLORESCING PROPERTIES 
Sulphate of Soda, each in a separate watch 
glass; the former from the 30th October to the 
4th December, and the two latter from the 31st 
October to the 4th December. 
Both these crystallized salts I had previously 
dried by exposure for a few days to the atmos- 
phere of the room in which the before-mentioned 
experiments are made. 
After one day’s exposure it was perceptible 
that the crystals of Sulphate had begun to 
effloresce. On the Ist November they had lost 
+ of a grain: on the 4th, 14. grain: on the 11th, 
34 grains: on the 16th, 54 grains: and on the 
4th December, 93 grains. I now discontinued 
the exposure; but if I had not done so the crys- 
tals would without doubt have lost water until 
they had become anhydrous. 
The anhydrous Sulphate was frequently 
weighed, and found not to gain any weight. 
On the Ist November, the crystals of Carbo- 
nate were found neither to have lost weight nor 
to have effloresced in the slightest degree: on 
the 5th some of the outside crystals were slightly 
effloresced, which I apprehend must be in con- 
