176 Proceedings of Indiana Academy of Science 
concentration per millimeter, and per minute, are higher, indicating 
that under the conditions examined, the use of alternating current 
increases the speed with which the nitric oxides are formed. It should 
also be noticed that the concentration per millimeter pressure change 
increases with the length of run using the induction coil, but decreases 
with alternating current, indicating that short alternating current runs 
are advantageous. 
Several runs were made to discover, if possible, the reason for the 
lack of consistent results, but the results were erratic, the pressure 
reversal varying both as to time and pressure decrease. The yields 
of nitric acid were different with each run and seemed to vary erratic- 
ally also. 
The usual practice before beginning a run was to sweep out the 
tube with dry fresh air. On one occasion this sweeping out process 
was omitted and the results were quite surprising. The tube had 
stood over night, the products of the last run having been blown out 
the night before. Instead of decreasing, the pressure increased 17 
mm. in 50 minutes, the titration at the end of the run showing only a 
trace of nitric oxides and no odor of ozone could be detected. Two 
3 Using Duplicate of Spicts’ 
Sey Alteenating Current 
FI cycles. 
Volts. Ky.+ TVs 44s 
erature "C. 
+The 
Tertiar 
x2* Fe 
rr) 
a 
20 «630 ao x” a o 10 20 30 40 So 
Time in Minutes. 
Fig- 5. 
other runs, D-25 and D-26, were made under all the same conditions, 
except that the tube was swept out with fresh dry air just before 
applying the voltage. The curves showing the characteristics of these 
three runs are found in Fig. 5. 
The pressure time characteristic with fresh air (run D-25) shows 
three distinct parts, viz., the pressure decrease, the pressure increase 
to initial pressure and the pressure rise after reaching the initial pres- 
sure. A very small yield of NO was obtained from this run, while 
