( 2 . 2.1 ) 
III. Ex traB of a Letter from Mr. Jofl. 
Nic. De l’Hle, F.R. S. to John Machin, 
Seer. R. S. <gy Tr. Aflr. Grejh. Dated 
Petersburg. r 7 Feb. 17 3 containing 
federal Literary Communications con- 
cerning the Con fruition of a Qiiick- 
fllver Thermometer, and his Obferva- 
tions on the Eclipfesof Jupiter V Satel- 
lites, Annis 17 3 1 ,and 173 i. Tranfated 
from the French ^Phil. Henry Zoll- 
man. F. R. S. 
I N order to have more fure Grounds for my Ex- 
periments of Natural Philofophy in this Country, 
and that they might be compared with thofe of 
other Countries, I applied myfelf this Winter to the 
Conftru&icn of Thermometers of Mercury , regu- 
lated by theExpanfion of that Fluid proportionally 
to its bulk. This Expanfion is indeed not very 
perceptible, confidering that Dr. Halley in the Ex- 
periments made by him upon it above 40 Years 
ago, which are related in Numb . 197, of the Fhi- 
lofophical Tranfattions ; found, that the faid Ex- 
panfion, by the Heat of boiling Water, was no more 
than 7 ~4 Part of the bulk of Mercury , the Experi- 
ment having been tried in the Months of February 
and March , when the Weather was cold enough, 
though it did not freeze. 
F f 2 
M. Ament 011s , 
