the "Point of Congelation . 29} 
which cooled more eafily and readily below the freezing point. 
In two inftances the cooling was more than n degrees. 
Having found that white vitriol, mixed with fnow, pro* 
duced a cold of 20% melting the fnow remarkably fall, I was 
induced to try the freezing point of its folutions. But though 
it diflolved very readily in water, yet the liquor it formed was 
fo turbid and thick, that little fatisfadtion could be derived 
from the experiments. The only numbers to be relied upon 
are the following, which agree fufficiently with the general 
refult. 
White vitriol. 
Proportion 
Freezing 
Freezing 
of water to 
point by the 
point by 
the fait. 
experiment. 
calculation. 
10 : 1 
O 
3 1 
O 
3 1 
5 : 1 
29! 
3 ° 
3 : 1 
281 
28* 
The third column is calculated 
from the laft experiment, in 
which the freezing point of a 
folution of one part of the 
white vitriol in three of water 
proved to be 28°^.. 
Thefe folutions cooled very ill, none of them having funk 
much below the freezing point, and the ftrongeft, which had 
a copious fediment, forming a cruft: of ice at the bottom of the 
tumbler, before it was reduced at all below the term of con- 
gelation. 
M. Achard, of Berlin, having alledged*, that borax in- 
ftead of railing the boiling point of water, like other faline 
fubftances, very fenlibly deprefles it, I determined, how- 
ever extraordinary the fadt might appear, to try whether it had 
* See Crell’s Chem. Annalcn, 1786, Vol I. p. 501. 
R r 2 any 
