on Mr. ntfT chins Experiments. * 519 
found folid; but from the refemblance of this to the three for- 
mer experiments, I think it much molt likely, that it did not 
begin to freeze till after the thermometer had funk to — 77°. 
In the fifth experiment the wooden thermometer was partly 
frozen before it was put into the freezing mixture, and the 
ivory one was at - 40°. On putting them into the mixture, 
they both role ; the latter, half a degree ; the former, many 
degrees; which thews that the part of the mixture in which 
they were placed was rather warmer than the freezing point, 
though that in which the fpirit thermometer was placed wa* 
colder ; but as there teems nothing to be learnt from this, it is 
not worth while entering into a detail of the circumftances. 
Though tliefe experiments do not ferve to Ihew what the 
freezing point of quicklilver is, yet they do not at all contra- 
dict the conclution drawn from the three former. 
If thefe experiments only had been made, I fhould have been 
inclined to fuppofe, that quicklilver froze with a lels degree of 
cold in vacuo than in the open air, as the quicklilver in the 
ivory thermometer was in vacuo, and that in the cylinder was 
not ; but* as in the three former experiments, the event was 
different, the quicklilver in the cylinder there freezing firft, I 
have no reafon to think that this is the cafe. 
Though in the lixth experiment the thermometer in the ap- 
paratus G froze without the quicklilver with which it was fur- 
rounded freezing, yet in trying the apparatus F in the lame 
mixture, this did not happen ; but, on the contrary, it afforded 
as linking a proof that the point of freezing quicklilver an- 
fwers to about - 40° on this thermometer as any ot Mr* 
Hutchins’s experiments; tor, on taking out the apparatus 
after it had been two minutes in the mixture, the quick- 
lilver in the cylinder was found frozen folid, the inclofed ther- 
Vol. LXXIII. U u mo me ter 
