the Point of Congelation. 305 
is probably no greater than a feventh or a fixth of common 
fait to the fal ammoniac. Is it poffible that Fahrenheit, 
finding a confderable difference in his experiments, took the 
mean between them for his zero, without any rdpedt to the 
different nature of the l'alts with which he operated ? It ap- 
pears, that he was at this time id little acquainted with the 
fuhjedt, as to coiifder his zero as the utmofl limit of cold. 
I come now to certain fob fauces which, by equal additions, 
feem to deprefs the freezing point of water in an increijing 
ratio . Thefe, as was mentioned before, are acids, alkalies, 
and fpirit of wine. I judge this to be the cafe from the fol- 
lowing experiments, though they are by no means fo full and 
extenlive as I could have wifhed to make them, had leifore 
permitted. 
The fpecifc gravity of the vitriolic acid I employed was 
1,837 at 62° of heat; its effedt upon the freezing point is 
fhewn by the following table. 
Vitriolic acid. 
Proportion 
Freezing 
Freezing 
of water to 
point by the 
point by 
acid. 
experiment. 
O 
calculation. 
C 
10 : i 
241 
22| 
5 : 1 
12 i 
12* 
4 : 1 
7i 
« 1 
/ * 
This table is confrudled in the fame manner as thofe for- 
merly given of the folution of fmple fairs ; the laf experi- 
ment, where the proportion is 4 : 1, being taken as the fan* 
dard for computation ; and the extreme difference between, 
the calculation and experiment is no lefs than 2°1, upon a 
reduction 
