THOMPSON. — ON THE EQUILIBRIUM OF THE SYSTEM. 441 



If p 3 = the total pressure during the run, which is greater than p on 

 account of the higher temperature, the pressure in millimeters of carbon 

 monoxide is computed by the formula 



_ m X .0821 X T X 760 X p z 

 P ~ 19.9 X pi 



in which T is the absolute temperature of the gas in the furnace at the 

 beginning and at the end of the absorption. 



At the end of the absorption the pressure of hydrogen in the absorp- 

 tion bulbs was only about half an atmosphere, consequently enough 

 hydrogen had to be let in to bring the pressure to one atmosphere, 

 after which the bulbs were again hung in the balance case and weighed 

 the following day. The variation due to temperature and pressure 

 change in the weight of hydrogen filling the bulbs was negligible. All 

 weighings given in the following are reduced to vacuo. The data thus 

 obtained after the above run were the following : 



Initial weight bulbs 175.3392 grams 



Final " " 175.3482 " 



Gain in weight 0.0090 " 



The time taken for absorbing the gas was 6 hrs. 



2h = 68.5 cm. of mercury 

 lh = 38.6 " " 

 p 3 = 89.0 " " 



, .00074 X .0821 X 285 X 760 X 89 

 whence Pco = 1 9 , 9 x 68.5 



= 0.86 mm. of mercury. 

 On opening the furnace white powder was found on the lid. 



Experiment 2. 



The same charge as used in Experiment 1 was ground up and re- 

 placed in the crucible. Part was tested with water and gave off acet- 

 ylene vigorously. It was heated for an hour to 1000° and evacuated 

 to a pressure of 0.05 centimeter of mercury. No carbon monoxide was 

 admitted. Hydrogen was let in to 6.72 centimeters in 1 hr. 40 min. 



