iSo Mr, Cavendish’s Account of 
expofed to the cold, was +9 0 . It muft be obferved, that 
though this part was in all probability at firft ftronger than the 
decanted part, yet at the time its freezing point was tried, it 
feems to have become rather weaker than that, owing to its 
expofure to the air. It was before laid, that the freezing 
point tried in the fecond manner is that of the decanted 
liquor ; fo that the freezing point of the decanted part feems to 
have been 13 or 14 degrees colder than that of the undecanted 
part ; though the difference of ftrength, if there was any, 
muft in all probability have tended to produce the contrary 
effedh 
The freezing point of N° 2. tried in the firft way, was — 26° ; 
t 
and that tried in the fecond was -30°, 01*26°; but yet the 
freezing point of the undecanted part was 26 or 30 degrees 
higher, namely, at zero ; a difference which could fcarcely 
have proceeded from the difference of ftrength. 
The freezing point of N° 3. could hardly differ much from 
+ 42 0 ; and that of N° 4. was about — 45 0 . 
It fhould be remarked, that when this laft acid, as well as 
N a 1. and 2. were expofed to a great cold, a fediment formed 
in them. This muft have been of a very different nature from 
frozen acid, as appeared both from its texture, which was foft 
and mucilaginous to the feel, inftead of being gritty as the 
frozen acid always was ; and alfo from its being not much in- 
creafed by an increafe of cold; and therefore feems to have 
been fome impurity feparated from the acid. The quantity 
was greateft in N° 4. ; but even in this, though it appeared 
great, it is likely that the real quantity was very fmall. 
Another bottle of acid, whole ftrength was ,659, was fent ; 
but Mr. M c Nab was not able to make this freeze. 
From thcfe experiments it fhould feem, that the freezing 
4 point 
