fome Attempts to freeze Quickfilver . 177 
thermometer flood at 36° below o. I began the ope- 
ration exactly at forty-five minutes paft eight : the in- 
ftrument being at 28° was put into a large tea-cup with 
the mixture as above, together with a Ipare tube, gra- 
duated by myfelf ; the quickfilver in the latter fubfided 
into the bulb, which was only 200° below o; in the 
ftandard thermometer it funk to 447 0 at fifty-nine mi- 
nutes after eight o’clock, which gave me great hopes of 
fucceeding ftill better than in my firft attempt, becaufe I 
had now a greater degree of cold in my firft cup than I 
had before in my third. Finding it did not go any lower, 
I removed it into a fecond cup, prepared as before ; but 
the quickfilver fliewed no alteration in it. After waiting 
a confiderable time, I removed it into a third ; but in the 
removal, the quickfilver rofe to 380° below o. I ima- 
gined I had put in too much fpirit in proportion to the 
fhow, and therefore added more of the latter, by which 
means it fubfided to 408°; and after ftanding at this 
point for fome time, it rofe to 406°; and foon after, at 
ten minutes after nine o'clock, it rofe with great celerity 
and full of bubbles, until it came to 160 0 above o, and 
in a minute after it reached the point of boiling water. 
On examining the inftrument, I found the bulb cracked 
and the quickfilver fluid, to my furprize and regret. 
REMARKS. 
1 imagine it is extremely difficult to afcertain the exacft 
degree at which quickfilver begins to freeze, becaufe 
no particular alteration or circumftance points out the 
Vox. LX VI. A a 
mo- 
