CARPENTER'S CALORIMETER. 31 



waste gases. The gases passed off through a carbonic acid 

 absorbing apparatus. 



To reduce to the minimum, or entirely suppress, the cor- 

 rection for temperature he regulated his gas-flow so that the 

 temperature was as much higher than the air at the close of 

 the experiment as it was lower at the beginning. This he 

 easily did by means of his hydrogen supply. If a liquid was 

 tested, it was vaporized and burnt in a specially devised 

 burner which allowed complete combustion of almost all com- 

 pounds not having too high a boiling-point. If too high for 

 heat vaporization, they were carried along by a current of air, 

 oxygen, or hydrogen, as seemed best adapted. 



The water of the calorimeter being weighed, the lower 

 portion was closed with a rubber stopper and by means of an 

 aspirator a pressure of 8 to 12 inches of water was put on the 

 apparatus to test the joints. When ready, the temperature 

 of the bath and the air was noted for some minutes, the gas- 

 holder reading taken, the burner placed in position, and the 

 test commenced. The depression produced by the aspirator 

 was about 0.4 inch during the whole test. The regularity of 

 the working was shown by a gauge registering the pressure. 

 When the temperature had reached the desired point the gas 

 and electric current were shut off, the burner removed, and 

 the opening closed again. The aspirator was used to draw 

 dry air, freed from CO, , through the apparatus to insure 

 removal of all waste gases. The apparatus was then allowed 

 to rest, taking the temperature at short intervals for fifteen 

 minutes. He then had all the data required. 



CARPENTER'S CALORIMETER. 



Prof. R. C. Carpenter devised a calorimeter especially for 

 coal determinations, which is a modification or extension of 

 Thomsen's. He has used it considerably in connection with 

 work he has been engaged on, and the results credited to him 

 in the tables at the end of the book were obtained with it. 



