the Point of Congelation . 291 
flop of the cooling, and the rapid depofition of fait; for 
inftance, a particular ebullition in certain parts of the liquor ; 
but any intelligible defcription of them would be too minute. 
Thefe were all the falts with an alkaline bafis which I tried. 
They all agreed as to the chief obje& of thefe experiments, 
namely, to determine how much the freezing point of water 
would be funk by dilfolving them in it in various proportions ; 
which by thefe experiments appears to be, as nearly as could 
be determined, according to the fimple ratio of the proportion 
each fait bears to the water. 
I now refolved to try a few falts with an earthy and metallic 
bafis. 
The common fal catharticus amarus of the {hops was the 
fpecimen I ufed of an earthy fait. It formed a turbid inele- 
gant folution, as if dirty; and with various proportions of 
water produced the following points of congelation. 
Sal catharticus amarus. 
Proportion 
Freezing 
Freezing 
of water to 
point by the 
point by 
the fait. 
experiment. 
calculation. 
16 : 1 
O 
3 r 
O 
3 l 
10 : 1 
30 
3°J 
4 • 1 
281 
28 
3 : 1 
26* 
264. 
2,4 : 1 
2 5 l 
25I 
The third column is calculated 
from the lafi: experiment, where 
the freezing point of a folution 
of one part of the fal catharti- 
cus amarus in 2,4 of water 
proved to be 25°^. 
No fait was depofited from the ftrongefi: of theie folutions ; 
and as that which I ufed was a deliquefcent ialt, it muft pro- 
bably have been in a valt proportion to the water, before any 
Vot. LXXVIIL R r fuch 
