496 Mr. Cavendish’s Experiments to determine 
In these three experiments, the effect of the weight appeared 
to increase from two to five tenths of a division, on standing an 
hour; and the thermometers shewed, that the weights were three 
or five tenths of a degree warmer than the air close to the case. 
In the two last experiments, I put a lamp into the room, over 
night, in hopes of making the air warmer than the weights, but 
without effect, as the heat of the weights exceeded that of the 
air more in these two experiments than in the former. 
On the evening of October 17, the weights being placed in 
the midway position, lamps were put under them, in order to 
warm them ; the door was then shut, and the lamps suffered 
to burn out. The next morning it was found, on moving the 
weights to the negative position, that they were 7°^- warmer 
than the air near the case. After they had continued an hour 
in that position, they were found to have cooled i°i, so as to 
be only 6° warmer than the air. They were then moved to the 
positive position; and in both positions the arm was drawn aside 
about four divisions more, after the weights had remained an 
hour in that position, than it was at first. 
May 22, 1798. The experiment was repeated in the same 
manner, except that the lamps were made so as to burn only 
a short time, and only two hours were suffered to elapse before 
the weights were moved. The weights were now found to be 
scarcely 2 0 warmer than the case ; and the arm was drawn aside 
about two divisions more, after the weights had remained an 
hour in the position they were moved to, than it was at first. 
On May 23, the experiment was tried in the same manner, 
except that the weights were cooled by laying ice on them ; 
the ice being confined in its place by tin plates, which, on 
