26! 
Mr. Kir wan’s Remarks on jpecific Gravities 
GQ‘4G/4j%G point to one cubic foot and 6 6,4.6 cubic inches. And if the 
dilatations are proportional to the degrees of heat throughout 
r 
r /a* (oj 23 0 /) the fcale, there mu ft be an augmentation of 3,136 cubic inches 
1 
2 ' 5 / 4 8 
A 
■per cubic toot, produced by every 10 degrees of heat. Both 
thefe points remain, therefore, to be determined ; firft, at what 
temperature a cubic foot of water weighs exactly 1000 ounces 
avoirdupois ; and,2dly, whether the dilatations produced by fuc~ 
ceffive degrees of heat are proportional to the degrees that pro- 
duce them. This laft point has indeed been handled by others, 
but with different views; and their determinations arenoteafily 
applicable to the prefen t queftion. 
To examine this matter experimentally, I ordered a hollow 
tinned iron cone to be made, of four inches diameter in the 
bafe, one-tenth of an inch diameter in the fummit infide, and 
to inches perpendicular height, whofe folid contents fhouldbe 
74 ' 3 42^961 cubic inches, but by a flight diminution of the dia- 
, ' meter, and a protuberance arifing from the foldering, I found 
■§yf v it to contain, in the temperature of 62% but 42,731 cubic 
inches, according to the eftimation of 1000 ounces to the 
cubic foot ; and having filed it by immerfion in boiling water, 
and taken it up at different degrees of heat, and weighed it 
When cold, I found its contents as expreffed in the following 
table ; the firft column of which fhews the degrees of heat at 
which it was taken up ; the fecond, the weight of the water 
contained in it;, the third, the diminution of weight occafioned 
by thofe degrees of heat ; the fourth, the fum of the diminu- 
tions of weight in the cubic foot, by the preceding degrees of 
heat ; the fifth fhews the weight of a cubic inch of water in 
each of thofe degrees of heat ; and the fixth, the augmentation 
of bulk in the cubic foot by every 20° of heat. The horizontal 
lines, marked thus ^ I have added from the experiments of Mr*. 
2 Black, 
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