High Frequency Corona Discharge 161 
The longer the time spent in the discharge the greater the concentra- 
tion of the ozone, but, owing to the reverse decomposition of the ozone, 
which occurs simultaneously, the increase in ozone concentration with 
time should be logarithmic as indicated by the dotted curve. The 
lag effect has operated against ozone production at first. 
‘An iron wire was also found to be unsuitable because of the large 
magnetic losses with high-frequency currents. A copper wire was 
found to be much more suitable, although it became gradually oxidized 
and covered with more or less nitrate with some “lag effect’, although 
much less than with platinum wires. Aluminum was found to be the 
best material for ozone production. 
An interesting “ionization pressure” has been noted at the Uni- 
versity of Illinois by Kunz and his students.“ The same effect was 
observed with the high-frequency corona. In Fig II are plotted some 
results. The discharge was passed through enclosed air and the pres- 
sure changes were followed by means of a manometer filled with the 
purified paraffin oil called “stanolax”. At A the discharge was started 
and stopped at B; after three minutes it was started again at C and 
at the end of one more minute of discharge was again discontinued. 
The sharp breaks are mostly due to the ionization pressure. They are 
much too sharp and extended to be caused simply by the heating of the 
gas. At the end the pressure drops below that of the atmosphere, 
indicating some kind of condensation reaction such as ozone formation. 
Typical results are given in Figs. III, IV and V. In Fig. III a 
No. 33 copper wire was used and the data for one spark gap width 
Cs AM PS Cee, f. wa LES 76 [LITER 
, hf 
Ny 9 ie i 
. BCE 
N 9 
LD 
VS | / 
d 
Fel 
D3 
Q 8 9g a o g > IS) 
n a AS) ie) y 
7UBE AIIPS. lr1179° VoLTs 214 / Cousorare 
Fig. II. A No. 33 copper wire was placed co-axially in an aluminum tube. The 
air flow rate was 280 ec. per min. The spark gap-width was 1.2 mm. Six variables 
are plotted against the gross primary watts as abscissa. I. gives the concentration 
curve in mg. per liter (g. per cu. M.). II. expresses the yield of ozone in mg. per 
coulomb of current flowing into the discharge tube. The efficiency of ozone production 
is plotted in curve III. in terms of mg. per watt hour (2g. per kilowatt hour). The 
other three curves give the electrical readings; IV. for the primary volts; V., the 
primary amperes and finally VI. gives the amperes of the discharge current as measured 
by a hot-wire ammeter. 
ta Phys. Rev. 8, 285 (1916) ; 10, 483 (1917). 
11-20320 
