the Point of Mercurial Congelation. 
Experiment IV. made January 7, 17S2. 
Time per 
Watch. 
Thermom. 
below O. 
Appara- 
tus. 
Spirit 
Thermom. 
Remarks and Occurrences. 
h * / // 
n 52 30 
11 53 0 
11 53 3 ° 
11 54 0 
11 54 30 
11 55 0 
11 5 53 ° 
11 56 0 
1 1 56 30 
53 
46 
42 
40 
39 
39 
39 
39 
38 
38 
38 
37 
37 
37 
37 
37 
37 
3 6 
27 
27 
27 
26| 
26 i 
26| 
26! 
26-! 
26 
Found the quickfilver wholly thawed in the cylinder. 
This experiment was made with the mercurial thermometer 
(A) and the apparatus (F) as in the firfl and fecond experiments. 
The day was clear, with little wind at W. by S. or W.S.W. 
which I have obferved to be generally the cafe in this country in 
the coldefl weather. The thermometers at 8 o’clock were as 
follows, according to the rotation of the letters from (A) to (G), 
39°1, 36°!* 35 0 , 25 0 , 25 0 , 34T, 34 0 below the cypher. The 
apparatus thermometer (F), after {landing at 42 0 and 41°! for 
a confiderable time, funk at once to 7 7 0 , not gradually or by 
jumps, but fuddenly, as a weight falleth. The great defcent of 
the quickfilver in the index thermometer (A) to 440° in the firfl 
freezing mixture I impute to the coldnefs of the weather, but 
was furprifed to find it did not fink more than io° lower in the 
fecond mixture ; and in the third it did not reach fo low as in 
the preceding, which, indeed, might be accounted for by the 
air growing warmer as the fun approached the meridian. At 
10 h. 6 'i I poured fome of the firfl mixture into the tumbler 
where the inflruments were immerfed in the fecond, but found 
it weakened it; I therefore mixed a frefla one at ioh. 16'. It 
is however remarkable, that after pouring in the firfl mixture 
