i6o Mr. Cavendish’s Account of fome 
fluid part ; fo that, though the fluid part was not ftrong enough 
to diflolve ftfow 4 » a cold greater than -—43°}, yet the whole 
acid together was ftrong enough to do it in a cold one degree 
greater. 
A circumftance occurred in the laft experiment which I can* 
not at all fee the reafon of; namely, a fmall part of the acid 
being poured into a faucer, before the addition of the fnow, it" 
toasin an hour’s time changed into folid ice, though the cold 
of the air, at the time the acid was poured out, was only — 4 i°| r 
and does not feem to have increafed during the experiment. 
17. On December 30, the other half of the fame acid had 
been tried in the fame manner ; at the beginning of the experi- 
ment not more than one-ninth part of the acid was fluid, the 
reft folid clear ice; its temperature was — 34°!, and that of 
the fnow nearly the fame; the greateft degree of cold produced? 
was ~42 0 |; and the- quantity of fnow employed was aboufr 
one-eighteenth of the weight of the acid; fo that the ftrength 
of the mixture was ,38. The freezing point of the acid thus- 
diluted appears to be about — 45°^; for by the increafe of 
warmth during the day-time, moft of, the congealed matter 
difl'olved ; but in the evening it began to freeze again, fo as to 
become thicker, its temperature being then — 45°!- ; and the 
next morning it was frozen folid, its- cold being one degree 
greater. 
18. On December 12, the diluted fpirit of nitre N* 139* 
whofe ftrength was ,175, was found frozen, its temperature 
being —17. The fluid part, which was full of thin flakes of 
clear ice, and was of the confiftence of fyrup, was decanted 
into another bottle, and fent back. Its ftrength was ,21, and 
was greater than that of the undecanted part in the proportion 
of ,21 to ,x6; fo that, as not much of the UHdecanted part was 
