374 A. W. Ewell-A 



tr in 



an Intense Electric Field. 



f event distances approach each other. The latter result may 

 be explained by the compensation of the reduction in electric 

 force when the electrodes are separated, by the increased 

 volume in which ionization occurs. The first result shows 

 that when the current is increased beyond the values repre- 



Fig. 4. Abscissae = volts. Ordinates = milliamperes. I, Electrodes 

 against -24 cm of window glass. II, -24 cm of glass + '30 cm of air. Ill, 24 cm of 

 glass and l-6ft cm of air. II' and III' are corrected curves of II and III 

 respectively and give the relation between the e.m.f. applied to the air and 

 the ionization current. 



ented by the familiar lower portions of the curves, the air 

 under normal conditions exhibits so called " negative resist- 

 ance," which has hitherto been demonstrated 'only under the 



