on the Subject of Heat. 207 



ameter of the thermometer bulb was 0.55 of an inch, 

 and its contents 0.08711 of a cubic inch. Taking now 

 from the contents of the globe (2.14466 cubic inches) 

 the contents of the thermometer bulb (0.0871 1 of a cubic 

 inch), there remain 2.05755 cu bic inches as the measure 

 of the space occupied by the substances by which the 

 bulb of the thermometer was surrounded. 



Although the above-mentioned substances occupied 

 this space, they were very far from filling it, as will be 

 observed without my calling attention to the fact ; on 

 the contrary, this space contained a large quantity of 

 air, which occupied and filled the small interstices of 

 the substances in question. 



For example, in one of the experiments the bulb was 

 covered with 16 grains of raw silk. As I had already 

 learned from experiment that the specific gravity of the 

 silk was to that of water as 1734 to 1000, it follows that 

 the volume of 16 grains of silk was equal to the volume 

 of 9.4422 grains of water. Further, as I cubic inch of 

 water weighs 253.185 grains, it follows incontrovertibly 

 that the space occupied by 9.4422 grains of water can be 

 reckoned at the highest at 0.037294 of a cubic inch, and 

 this amount of water (9.4422 grains) corresponds in 

 volume to 1 6 grains of silk. 



We know, however, that the space which this small 

 quantity of silk (0.037294 of a cubic inch) occupies is 

 2.05755 cubic inches; hence it appears that, since 

 0.037294 is to 2.05755 as i is to 54, the silk which I 

 used in the experiment in question could not fill more 

 than -5^ of the space in which it was confined. 



The longer we meditate upon these investigations, 

 the more we are struck by the importance of the 

 results that follow from them. I have never been 



