6 o 
Sir Benjamin Thompson's 
Heat lost. 
Exp. 16. 
Exp. 17. 
Exp. 18. 
70° 
- 
. 
6o° 
82" 
84" 
83" 
50° 
96 
95 
95 
4°° 
ll8 
117 
11 6 
3°° 
152 
153 
151 
20° 
221 
221 
220 
10° 
38° 
377 
377 
Total times' 
IO49 
10 47 
1042 
The difference of the times of cooling in these three experi- 
ments were extremely small ; but, regular as these experiments 
appear to have been in their results, they were not more so than 
the other experiments made in the same way, many of which 
were repeated two or three times, though, for the sake of bre- 
vity, I have put them down as single experiments. 
But to proceed in the account of my investigations relative 
to the causes of the warmth of warm clothing. Having found 
that the fineness and equal distribution of a body or substance 
made use of to form a covering to confine heat, contributes so 
much to the warmth of the covering, I was desirous, in the 
next place to see the effect of condensing the covering, its 
quantity of matter remaining the same, but its thickness 
being diminished in proportion to the increase of its density. 
The experiment I made for this purpose was as follows : — 
I took 16 grains of common sewing silk, neither very fine nor 
very coarse, and winding it about the bulb of the thermometer 
in such a manner that it entirely covered it, and was as nearly 
as possible of the same thickness in every part, \ replaced the 
thermometer in its cylinder and globe, and heating it in boiling 
