PHYSICS, CHEMISTRY AND ENGINEERING 151 



A NEW LAW RELATING IONIZATION PRESSURE 



AND CURRENT IN THE CORONA OF 



CONSTANT POTENTIALS 



By Earle H. Warner, University of Illinois 



The "corona" is the glow which surrounds conductors 

 when there exist high potential differences between them and 

 neighboring conductors. 



Mr. Farwell has shown that at the instant the corona ap- 

 pears the pressure in the corona apparatus increases. It was 

 the object of the experiments which have been performed to 

 test the relationship between the ionization pressure and co- 

 rona current. 



The corona apparatus was of wire and co-axial cylinder 

 type. The continuous potential was obtained from a battery 

 of forty continuous current, shunt wound, 500-volt gener- 

 ators connected in series. The corona current was measured 

 with a D'Arsonval galvanometer. The increase in pressure 

 was measured by a Bristol aneroid pressure meter. Experi- 

 ments have been performed with dry air, hydrogen, nitrogen 

 and carbon dioxide in the corona tube. In every case, with 

 the wire positive, the ionization pressure is exactly propor- 

 tional to the corona current. With the beads, which accom- 

 pany the wire negative, the pressure varies with the arrange- 

 ment of the beads and since these are not stable it is impos- 

 sible to accurately determine the desired relationship. 



(Completed paper published in Physical Review, Vol. 

 XVIII, No. 3, September, 1916.) 



