in Fluids. 247 



ence only, that in this second trial the water through 

 which the Heat was made to pass, instead of being pure, 

 was mixed with a small quantity of some fine substance 

 (such as eider-down, for instance), which, without alter- 

 ing any of its chemical properties, or impairing its flu- 

 idity, served merely to obstruct and embarrass the mo- 

 tions of the particles of the water in transporting the 

 Heat, in case Heat should be actually transported or car- 

 ried in this manner, and not suffered to pass freely 

 through liquids. 



The body which received the Heat, and which served 

 at the same time to measure the quantity of it communi- 

 cated, was a very large cylindrical thermometer. (See 

 Plate I.) The bulb of this thermometer, which .is con- 

 structed of thin sheet-copper, is cylindrical, its two ends 

 being hemispheres. 



Its dimensions are as follows : 



~. . c { Diameter 1.84 inches. 



Dimensions or ' 



... r , , Length 4.00 " 



the bulb of the 4 



, Capacity or contents. . 13.2099 cubic inches, 



thermometer. * . . 



I External superficies . . 28.834 superficial inches. 



The thickness of the sheet-copper of which it is 

 constructed is 0.03 of an inch. It weighs, empty, 1846 

 grains, and is capable of containing 3344 grains of water 

 at the temperature of 55. This copper bulb has a glass 

 tube, 24 inches long, and T % of an inch in diameter, 

 which is fitted by means of a good cork into a cylindri- 

 cal tube or neck of copper, one inch long, and -j 6 ^- of 

 an inch in diameter, belonging to the metallic bulb. 



This thermometer, being filled with linseed-oil and its 

 scale graduated, was fixed in the axis of a hollow cylin- 

 der constructed of thin sheet-copper, 11^ inches long, 

 and 2.3435 inches in diameter internally. This cylinder, 



