[ 374 ] 
of j whether air be mixed with, or neceflary to, its 
formation ; as alfo how far its power of refinance 
may reach ; are probably not yet known, to a proper 
degree of exa&nefs. Niewentit fixes the expanfion 
of a cubical inch of water, converted into fteam, at 
13365", Dr. Defaguliers at 14000, and Mr. Payne 
at 4000 times. The great fcope in this fubjedt 
from a plenum to a vacuum, if I may be allowed the 
expreflion, as alfo the very ufeful purpofes, to which 
it has already been, and pofiibly may be flill further 
applied, will, I hope, be an inducement to thofe, 
who are much better qualified, to proceed in fo 
ufeful an inquiry. 
,u 
XLVI. Obfervatio Eclipfis Euruz Die 27 Mar- 
tii, Ann. 1755. habit a UliJJipone in Domo 
Patrum Congregationis Or at or ii a Joanne 
Chevalier ejufidem Congregationis Prejby- 
tero , Regime Londinenfis Societatis Socio , 
Regiceqae Parifieniis Scientiarum Aca- 
demia? correfiponde?ite . 
Tubo optico 8 pedum peradta eft obfervatio coelo 
' lereno, claroque. 
Hora poftnieridiana 
IMMERSIONES. temporis veri. 
h / // 
Read Dec. 8,'l'Nitium penumb raedubium 10 29 fo 
1 757 * Initium eclipfis dubium 10 33 35" 
Certe jam incaeperat 10 34 05 
Umbra ad mare humorum 10 44 00 
Umbra 
