•42S 



On the Determination of the 



[Dfx. 



Temperature 

 of the air sur- 

 rounding the 

 calorimeter 



Temperature 

 lof the calori- 

 meter. 



45 990° 



83025° 



No. 1. 



Thermometers. 



No. 2. 



140-954° 



No. 3. 



151-286° 



145-74S" 



The temperature of the calorimeter was then artificially raised 

 ahout l'l°, and the current of water made to circulate as before. 

 The temperature of the calorimeter gradually sunk • and when 

 it had nearly reached its minimum, the following observations 

 were made : — 



Temperature | Temperature 

 of the sur-|of the calori- 

 rounrlingr air. meter. 



45-966° 



83-503° 



No. 1. 



140-756° 



Thermometers. 

 No. 2. 



No. 3. 



151-340° 



14559S 



In these experiments the current of water was such that 

 583-01 grains troy of water passed in ten minutes. 



If we examine with attention the state of the thermometers 

 Nos. 1, 2, 8, we shall perceive, that for distances so small as 

 those in our apparatus, the following proposition may be consi- 

 dered as true. When a regular current of hot water passes 

 through a vertical tube, if thermometers be placed in its centre, 

 at equal distances from each other, the difference between two 

 neighbouring thermometers will be proportional to the excess of 

 the temperature of the water above that of the surrounding air. 



We cannot therefore commit an error of much importance, if 

 we suppose that the current of hot water, in going from ther- 

 mometer No. 1 to the calorimeter, lost 4*86 of its heat, and 

 entered into the calorimeter at the temperature of 135 - 59°. 



We ascertained, by experiment, that it issued out at the same 

 temperature as that of the calorimeter. 



It follows from this experiment that a current of water 

 amounting to 583-01 grains in ten minutes, by losing 52-330° 

 of its heat, kept the calorimeter higher than the surrounding air 

 by 35-283°. 



We see by the first table that 21!)f>*4 cubic inches of air, or 

 723*71 grains, passing through the calorimeter every ten mi- 

 nutes, and losing 130*347° of heat, kept its temperature ele- 

 vated above the ambient air 28321°. If we bring by calculation 

 the results of the experiment on the current of water, to what 

 they would have been under the same circumstances as in the 



