268 M?\ Kir WAN's Remarks onfpecific Gravities 



point to one cubic foot and 66,46 cubic inches. And if the- 

 dilatations are proportional to the degrees of heat throughout 

 the fcale, there mufl' be an augmentation of 3,136 cubic inches 

 j^tT cubic foot, produced by every 10 degrees of heat. Both' 

 thefe points remain, therefore, to be determined ; firil, at what 

 temperature a cubic foot of water weighs, exaflly 1000 ounces 

 avoirdupois ; and,2dly, whether the dilatations produced by fuc- 

 cefiive 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 j and their determinations are not eafily 

 appHcable to the prefent queftion. 



To examine this matter experirnentally, I ordered a hollow 

 tinned iron cone to .be made, of four inches diameter in the 

 bale, one-tenth of an inch diameter in the fummit infide, and 

 10 inches perpendicular height, whofe folid contents fliould be 

 42,961 cubic inches, but by a flight diminution of the dia- 

 meter, and a protuberance arifuig from the foldering, I found 

 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 filled it by immerfion in boiling w^ater, 

 and taken it up at different degrees of heat, and weighed it 

 when cold, I found its contents as exprefled 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 thole degrees of heatj the fourth, the fum of the diminu- 

 tions of weight in the cubic foot, by the preceding degrees of 

 heat ; the fifth fhews tlie 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 *, 1 have added from the experiments of Mr* 



2 Bladh, 



