the Point of Congelation . 2S5 
26°, it would not have juft loft the difference between the pro* 
portions of 6 : 1 and 8:1, but would have depofited more of 
the fait, fo that now at 26° it would contain perhaps only a 
tenth of nitre ; as if the formation or exiftence of fome cry- 
ftals in the folution facilitated the reparation of the fait, or 
conftituted an attractive power counteracting the attraction of 
the fait to the water. It would have required a particular fe- 
ries of experiments to afcertain this as a faCl ; but feveral 
obfervations incline me to believe it is fo; and the con- 
fequences to be drawn from it would be fufficiently curious, 
and applicable to many points of theory. Of the fame 
nature, perhaps, is another circumftance already hinted 
at, that after the folution has begun to form cryftals of 
nitre, the depofition proceeds with increafed rapidity as the 
cooling goes on. This may, indeed, be owing to the attrac- 
tion of the water to the fait decreafing in a progreftive ratio 
with each degree of cold ; but it may alfo depend on the 
attraCling furfaces being multiplied as more cryftals are formed : 
and ftirring the liquor feems to haften the progrefs of the de- 
pofition ; which may be aferibed to its bringing frefti portions 
of the folution perpetually to thofe attracting furfaces ; for, if 
there be fuch an attraction, it can fcarcely be fuppofed to take 
place at any fenfible diftance. 
Upon the whole it feems evident from the preceding table, 
that the effeCt of nitre, like that of common fait, is to de- 
preis the freezing point in the limple ratio of its proportion to 
the w T ater ; which w r ill be found univerlally true when allow- 
ance is made for the depofition and other fources of fallacy 
already enumerated. 
This nitre produced, with fnow, a cold of between 26° and 
2 7 0 . 
Q.q 2 
As 
