the Congelation of ^uickflver. 347 
pened very remarkably in fome of the experiments at Hudfon’s 
Bay, and in various meteorological obfervations to be defcribed 
hereafter. 
Mr,, hutchins mentions, in the remarks upon his ninth ex- 
periment, that the internal furface of the congealed quickiilver, 
after the fuperincumbent frigorific mixture and fluid metal had 
been decanted off, “ was every where very rough, and of a 
“ dull white, refembling that of a filver fpoon in common 
“ ufe likewife, that “ the lump fhe wed very weak cohefion, 
“ crumbling to pieces under the ftrokes of a hammer, and had' 
“ not the ufual polifh.” Thefe differences he afcribes to an 
efie6t produced, by the fpirit of nitre in the mixture, upon the- 
quickiilver, with which it came into immediate contact ; but I 
am rather of opinion, that they were occafioned chiefly by the 
unconfined cry Utilization of the mercury in the open gallipot 
employed for this experiment, fimilar appearances having al- 
ways been obferved when it congealed under fuch circum- 
ffances. 
It is here neceffary to take notice, that the thermometers fent 
out to Mr. hutchins, even thofe made with quickiilver, did 
not exactly agree together. From his Table of Comparifon we 
may colletff, what fubfequent experiments have confirmed, that 
- 40° upon the two fmall ones with ivory fcales, anfwered 
to - 44 0 or -45 0 upon one of the large thermometers, that 
which had the ball on top, and to ~42° or — 43 0 upon the 
other. Now as this lafr was the inftrument which Mr. 
hutchins plunged into the quickiilver he attempted to freeze 
in his eighth experiment, and which funk only to — 4c 0 , it is 
no wonder that he did not then perceive any marks of conge- 
lation, the cold really wanting two or three degrees of being 
fufficient for that effc£L 
The 
