( 94 ) 
Pofftion, its (horter Leg appearing above the Water, 
(which was purpofely fo contriv’d to prevent any Incon- 
venience that might arife by the Waters getting into if, 
and to give a free liberty for the preflbre ot the outward 
Air to exercife its full power.) When the Spirit ot Wine 
had afcended by the heat of the Water into its fmall 
Ball on top, which I thought was neceffary, that I might 
make my Obfervations with the more exadtnefs upon its 
Defcent ^ fuppohng by that time it lliould fall to the 
Degree defign’d to begin at, that the Spirit in the Ball, 
would haue receiv’d an equal Degree of heat in all its 
Parts. Accordingly I began my Obfervations, when it 
had defcended to 130 Degrees above the Freezing Point 5 
at which time, I found the length of the Column of 
Air, from the clofed end of the Syphon, to the near- 
eft Surface of the Quickfilver, to be )aft 144 tenths of 
of Inches. After the Spirit had defcended 10 Degrees 
lower, ^he Air, which before pofTcfs’d 144 Parts, lack’d 
one of them now 5 and fo on fucceflively at every 10 
Degrees defcent of the Spirit, the Column of the con- 
tain’d Air was leffen’d in its length one exa6t tenth. When 
it had defcemied to 30 Degrees above the^reezing Point, 
the Air was found to polTefs but 134 of the prementioii- 
ed Parts : So that from hence it will be eafie to conclude, 
that at the Freezing Point, the Air in the Syphon would 
be reduc’d to 3 tenths lefs than the laft Obfervation. 
And confequently at 50 Degrees below the Freezing 
Point, (which I am informed is the greateft degree of 
Cold that has happen’d in our Climate,) it would be re- 
duc’d to 1 26 Parts of the whole, and in that ftate would 
be one eighth more denfe than when at the greateft De- 
gree of our Natural Heat : and the Reafon why I could 
not prove this latter part by Experiment was, that when 
I came to expofe the Thermometer and Syphon in the 
open Air, or Freezing Mixture, the Syphon would in- 
ftantly 
