fome Attempts to freeze Quickfilver. 17 5- 
According to the inftrudtions you were fo obliging to 
give me, concerning the congelation of quickfilver by 
cold, I made my firft attempt to produce that extraordi- 
nary phaenomenon on the 19th January, 1775. The 
thermometer at eight o’clock in the morning was at 
37 0 below o; but between ten and eleven it flood at 
28°. I took the fame thermometer and the heft fpare 
tube I had, which admitted only of 250° below o, and 
immerled them both together in a large tea cup filled with 
fnow, and poured on fp. nitri fumans Glauberi until the 
l'now was diffolved ; but finding it did not cover the bulbs, I 
added more fnow and fpirit until the bulbs were entirely 
covered in the mixture, which was now liquified: the 
quickfilver fubfided very gradually to 130°, and then 
flopped. I had another cup at hand, and mixed fome 
fnow and fpirit in it fo as to liquify the mixture, and re-, 
moved both the thermometers into it ; but found the 
ftandard thermometer, by which I mean the inftrument 
graduated by Meff. nairne and blunt, London, had 
rifen in the removal to 1 io° below o. As the mixture 
in this fecond cup did not cover the bulbs, I added more as 
before, and alfo poured fome out of the firft cup. The 
fpare tube, graduated by myfeif, flood in this cup at 
130°; but the ftandard fell deliberately to 263, where 
it flood again. I therefore prepared a third cup as be- 
fore ; the quickfilver did not afcend in the removal, but 
when immerfed it fell very fwiftly: that in the fpare 
tube funk into the bulb, and that in the ftandard de- 
fended much quicker than before, until it came 10400° ; 
after. 
