PHYSICS: H. B. LEMON 293 
men, the carbonization of which was for 3 hours at 670°C. The first run 
shows an extremely active adsorption. Successive outgassings were not 
now identical but were as indicated below: 
First 4.5 hours at 633°C. 
Second 0.5 hours at 800°C. 
Third 0.5 hours at 850°C. 
Fourth 0.5 hours at 875°C. 
Fifth 4.0 hours at 640''C. 
Sixth 0-7 hours at 905°C. 
The first four runs show a cumulative loss of activity as result, of high out- 
gassing temperature. In the fifth the activity is in part restored by pro- 
longed outgassing at the lower temperature and in the sixth it is again almost 
totally destroyed. Quartz tubes are unsuitable for use for the high tempera- 
ture work because of their devitrification by the hot carbon vapor. 
Figure 4, repeating the sixth run shown in the preceding, carried the same 
sample back to high activity in four subsequent outgassings which were as 
follows: 
Seventh 22.0 hours at 650°C. 
Eighth 22.0 hours at 500°C. 
Ninth 44.0 hours at 650°C. 
Tenth 1.0 hours at 840°C. 
A sluggishness of behavior is apparent after this much use as indicated in the 
long times necessary to produce a change in quality and also in the failure to 
respond as before to a temperature higher than 800. 
