126 Dr. Blagden’s Experiments on the 
frigorific mixture, made with fnow and common fait. This 
was the method 1 ufed in moft of the following experiments, 
fometimes employing ice infiead of fnow, fubftituting a glafs 
jar or cylinder inftead of a tumbler, and filling the vefifel to a 
greater or lefs height above the bottom. I found that, in the 
frigoric mixture, the diftilled water readily funk many degrees 
below 32°, ftiil continuing fluid ; and by repeating the experi- 
ment with care, I feveral times cooled it to 24% 23°!, and 
even almoft to 23 0 . The temperature was afcertained by means 
of a fmall thermometer with a Aiding fcale ; and though the 
water was not of the fame degree of cold throughout, yet the 
difference, when the experiment had been well conduced, was 
not confiderable ; and I was particularly careful that the ther- 
mometer fhould not touch the fides or bottom of the glafs, fo 
as to be affe&ed immediately by the cold of the mixture. 
From thefe experiments therefore it feemed evident, that the 
property of being cooled below the freezing point did not de- 
pend on extraneous admixture, efpeciailv as I found, by com- 
parative trials, that common pump-water would fcarcely ever 
bear to be cooled fo much. A11 ambiguity, however, {fill 
remained, on account of the air which is always mixed with 
water that has lain expofed to the atmofphere. In order to 
determine what might be afcribed to this circumftance, I put 
fome of the fame difiilled water over the fire to boil, in a clean 
filver vefifel, and kept it in violent ebullition for a confiderable 
time. In a few minutes after it had been taken off the fire, 
and before it was nearly cold, I fet it in the frigorific mixture 
after the ufual manner ; when, inftead of freezing more rea- 
dily, it bore to be cooled two degrees lower than I had ever been 
able to reduce the unboiled water, not congealing till the ther- 
mometer in it had funk to 21 0 . Subfequent experiments were 
attended 
