Mr. Haycraft on the Specific Heat of the Gases. 207 



passed. This will be easily explained, when we consider that 

 a thermometer can never indicate the true temperature of any 

 gas or vapour, which is itself pervious to the radiation of heat 

 or cold from surrounding bodies. On this account the ther- 

 mometers indicated a temperature of the gases much lower than 

 the true one, they being necessarily placed so near the calori- 

 meters, which usually contained water of a temperature nearly 

 100° lower than that of the gases. In the same manner, the 

 gases issuing from the calorimeters appeared to have a tem- 

 perature something lower than that of the calorimeters them- 

 selves, being surrounded with objects of a lower temperature 

 than that of the calorimeter. 



Experiments on Oxygen Gas. 

 No. l. • 

 Having filled the part A with oxygen gas procured from 

 the black oxide of manganese, and every arrangement being 

 made as before, the following results were observed : 



Temperature of Calori- 

 meter A, containing 

 ..... Oxygen Gas. 



At the beginning ") 

 of experiment, J 

 After 5 minutes, 

 After 10 minutes, 

 After 15 minutes, 

 After 20 minutes, 



%i> 2 



U1 20 

 "»7 2 

 '2 0~ 



71 



At the beginning ") 

 of experiment, J 

 In 10 minutes, 

 In 15 minutes, 

 In 20 minutes, 



A 



56-6° 



66-16 

 71 



?V<7 



No. 2. 



Of Calorimeter B, 

 containing At- 

 mospheric Air. 



4.KO .5 



^n 



B 



56-4° 



66-14 

 70-18 



74. 2 



Inferred Capacities. 



10000 



10000 



10019 



9982 



10000 



10000 

 10000 

 10000 



The temperature of the gases entering the calorimeters 

 was equal, being each 137°. The gas contained in the gaso- 

 meter before the apparatus was filled, indicated 98° per cent, 

 of oxygen, by the test of sulphuret of lime. After the expe- 

 riment was concluded, that contained in the apparatus indi- 

 cated 91° per cent. 



[To be continued.] 



XXXVI. On 



