1813.] Specific Heat of the different Gases. 4-11 



Temperature of the air. Temperature of the calorimeter. 



44-830° 76-359° 



41-830 76460 



44841 76-543 



44-910 76-626 



44 929 76-696 



44-953 76-797 



4 i-969 76-847 



44 969 76-879 



44-969 76-896 



From this table we see that the current of hot air was capable of 

 heating the calorimeter only about 017° the last ten minutes. 

 The calorimeter was then raised to the temperature of 78-073°. The 

 current of hot air was continued, and the thermometer observed 

 every ten minutes. The results were as follows : — 



Temperature of the air. Temperature of the calorimeter. 



45199° 78073° 



45-176 78-035 



45-153 77-940 



45-153 77-857 



45153 77 806 



45- 153 77-790 



45-176 77770 



The calorimeter during the last ten minutes sunk enly 0-02°. We 

 obtain the maximum effect by taking the mean of the results fur- 

 nished by these two sets of observations. 



The result is, that the current of hot atmospherical air rendered 

 the calorimeter stationary at the temperature of 77-333°, that of 

 the ambient air being 45-172 . 



Note 3d. 



We may compare the cooling of a hot body placed in air whose 

 temperature is constant to the motion of a body, M, which goes in 

 a direct line towards a fixed point, D, with a velocity always pro- 



C 



m •- ■ 1 d 



portional to the space, M D, which remains to be passed over. 

 The fixed point, 1), is the temperature of the surrounding air, and 

 the space, M D, is the variable excess of the temperature of the 

 hot body above that of the surrounding air. Hence we will apply 

 to the motion of such a body the reasoning on which is founded tire- 

 formula cited in the paper. 



This formula is an expression fbr the space, S, which the body 

 setting out from C, the distance of which from D is known, will 



over in the time, T ; supposing it to preserve daring the whole 

 notion the initial velocity, V, which it had in C. Nothing would be 



lex than the determination of this space, if V were known: for 



