THOMPSON AND LOMBARD. — NITROGEN IN CALCIUM CYANAMIDE. 259 



tained in both directions at 1160 without a catalyzer, calcium chloride 

 was added to the charge for this experiment, to act as a catalyzer.^ 

 The charge consisted of 22.5 grams of calcium carbide and 2.5 grams 

 of dry calcium chloride, well mixed together. 



Current in 

 Time. Kilowatta. Pressure. 



Jul]) 1. 



Since the pressure had become fairly constant, some nitrogen was 

 pumped out. 



2.35 P.M. 4.10 19.6 



4.45 " 4.07 21.8 6.10 1050 



The constant pressure from the other direction is 22 millimeters. 

 The mean value at 1053° is 22.8 millimeters. With the same charge 

 the following experiment was made at a higher temperature. 



Here the pressure had become nearly constant, so nitrogen was 

 admitted. 



3.15 P. M. 4.99 108.7 



4.50 " 4.98 78.5 



July 6. 8.30 A. M. 4.97 74.4 



2.00 '• 5.01 67.2 5.90 1115 



Absorption was still taking place, but so slowly that the experiment 

 was stopped. The mean of 67.2 and 57.7 is 62.5 millimeters at 

 1117° C. 



Experiment 13. 



The charge for this experiment was 22.5 grams of calcium carbide 

 and 2.5 grams of calcium chloride. 



* That the chlorides of the alkali earth metals act in this way was discov- 

 ered by Polzenius; see Bredig, Z. f. Elektroch., 13, 69 (1907). 



