288 
Sir Benjamin Thompson’s 
to the upper end of the cylinder, was 18 inches, and the freez- 
ing point upon the thermometer fell about 3 inches above the 
bulb; confequently it lay about ij inch above the junction 
of the cylinder with the globe, when the thermometer was 
confined in its place, the center of its bulb coinciding with the 
center of the globe. Through the ftopple which clofed the 
end of the cylinder pafled two fmall glafs tubes, about a line 
in diameter, which being about a line longer than the ftopple 
were flopped up occafionally with fmall floppies fitted to their 
bores. Thefe tubes (which were fitted exadtly in the holes 
bored in the great ftopple of the cylinder to receive them, and 
fixed in their places with cement) ferved to convey air, or any 
other fluid, into the glafs ball, without being under a neceflity 
of removing the ftopple doling the end of the cylinder; which, 
in order to prevent the pofition of the thermometer from being 
eafily deranged, was cemented in its place. 
I have been the more particular in the defcription of thefe 
inftruments, as I conceive it abfolutely neceflary to have a 
perfedt idea of them in order to judge of the experiments made 
with them. 
With the inftrument laft defcfibed (which I have called 
thermometer N° 3.) I made the following experiment. It was 
upon the 1 8th of July laft, in the afternoon, the weather va- 
riable, alternate clouds and fun-fhine ; wind ftrong at S.E. 
with now and then a (pr inkling of rain ; barometer at 27 
inches io| lines, thermometer at 18 0 }, and hygrometer va- 
riable from 44 0 to extreme moifture. 
In order to compare the refult of the experiment made with 
this thermometer with thofe made with the thermometer N° 2. 
I have, in the following table, placed thefe experiments by the 
fide of each other. 
(Exp. 
