2 7 6 Thompson’s 
to fay, rill the mercury in the inclofed thermometer flood at 
1 8°, I took it out of this veiTel and plunged it fuddenly into 
a velfel of boiling water, and holding it in the water (which 
was kept conftantly boiling) by the end of the tube, in fuch a 
manner that the glafs ball, in the center of which was the 
bulb of the thermometer, was juft fubmerged, I obferved the 
number of degrees to which the mercury in the thermometer 
had arifen at different periods of time, counted from the mo- 
ment of its immerfion. Thus, after it had remained in the 
boiling water i min. 30 fee. I found the mercury had rifen 
from 1 8° to 27 °. After 4 minutes had elapfed, it had rifen to 
44%V;- and at the end of 5 .minutes it had rifen to 4§° X V 
Experiment N. 0 2- 
Taking it now out of the boiling water I fuffered It to cool 
gradually in the air, and after it had acquired the temperature, 
of the atmofphere, which was that of 1 5 0 R. (the weather 
being perfectly fine), I broke off a little piece from the 
point of the fmall tube which remained at the bottom of the 
glafs ball, where it had been hermetically fealed, and of courfe 
the atmofpheric air ruftied immediately into the ball. The ball 
furrounding the bulb of the thermometer being now filled with 
air (inftead of being emptied of air, as it was in the before- 
mentioned experiment), I re-fealed the end of the fmall tube at 
the bottom of the glafs ball hermetically, and by that means 
cut off all communication between the air confined in the. hall 
and the external air; and with the inftrument fo prepared I 
repeated the experiment before-mentioned ; that is to fay, I put 
it into water warmed to 18% and when it had acquired the tem- 
perature 
