58 
Sir Benjamin Thompson's 
or in larger masses, with larger interstices, as the ravel ings of 
cloth, or cuttings of threads. 
If heat passed through the substances made use of for covering, 
and if the warmth of the covering depended solely upon the 
difficulty which the heat meets with in its passage through the 
substances, or solid parts , of which they are composed ; in that 
ease, the warmth of covering would be always, cceteris paribus, as 
the quantity of materials of which it is composed ; but that this 
is not the case, the following, as well as the foregoing experi- 
ments clearly evince. 
Having, in the experiment N° 4, ascertained the warmth of 
16 grains of raw silk, I now repeated the experiment with the 
same quantity, or weight, of the ravelings of white taffety, and 
afterwards with a like quantity of common sewing silk, cut into 
lengths of about two inches. 
The following table shows the results of these three experi- 
ments : 
Heat lost. 
» 
b0 
CD 
£ 
a 
Ravelings of 
taffety, i6grs. 
Sewing silk cut 
into lengths, 
i6grs. 
Exp. 4. 
Exp. 14. 
Exp. 15. 
7O 0 
— 
— 
— 
6o° 
94 " 
90" 
6y" 
5 o° 
110 
106 
79 
40 0 
153 
128 
99 
3 °° 
185 
172 
135 
20° 
2 73 
24 6 
W5 
10° 
489 
4 2 7 
34 2 
Total times. 
1284 
1169 
9*7 
