in Fluids. 249 



The thermometer being in its place, there is on every 

 side a void space left between the bulb of the thermom- 

 eter and the internal surface of the brass cylinder in 

 which it is confined, the distance between the external 

 surface of the bulb of the thermometer and the internal 

 surface of the containing cylinder being 0.25175 of an 

 inch. This space is designed to contain the water and 

 other substance through which the Heat is made to pass 

 itito, or out of, the bulb of the thermometer, and the 

 quantity of Heat which has passed is shewn by the 

 height of the fluid in the tube of the thermometer. The 

 quantity of water required to fill this space and to cover 

 the upper end of the bulb of the thermometer to the height 

 of about ^ of an inch was found to weigh 2468 grains. 

 As the thermometer was plunged into this water, it was, 

 of course, in contact with it by its whole surface, which, as 

 we have seen, is equal to 28.834 square inches. 



The bulb of the thermometer being surrounded by 

 water, or by any other liquid or mixture, the conducting 

 power of which was to be ascertained, a cylinder of cork 

 something less in diameter than the brass cylinder, about 

 half an inch long, with a hole in its center, in which the 

 tube of the thermometer passed freely, was thrust down 

 into the brass cylinder, but not quite so low as to touch 

 the surface of the water or other substance it contained. 

 This cylinder, or disk, was supported in its proper place 

 by three projecting brass points or pins which were fixed 

 with solder to the outside of the metallic neck of the 

 bulb of the thermometer. 



As soon as this disk of cork is put into its place, the 

 upper part of the hollow brass cylindrical tube is filled 

 with eider-down, and it is closed above with its cork 

 stopper, the tube of the thermometer, which passes 



