180 C. Barns — Distribution of Nuclei. 



sure difference S^>30 cm , by placing a gold leaf electrometer, 

 properly insulated, in the condensation chamber. The loss of 

 charge in damp air is at first surprisingly small ; nevertheless 

 the experiments are very difficult and we were unable to come 

 to a conclusion. A decision will probably be reached by aid 

 of the oscillating coronas mentioned in § 6. 



8. Successively increasing times of exposure to ^-radia- 

 tion. — After this digression experiments were resumed with 

 the apparatus as shown in the figure. The pressure difference 

 hp — 17 cm was used throughout, as this is well within the lower 

 limit of spontaneous condensation for the given receiver, 

 while coronas may be obtained with X-ray nuclei for pressure 

 differences even lower than hp = 10 cm . Such coronas are 

 vague, however, until the rain nuclei are thrown out, and on 

 second exhaustion (w-39000, s = 4*8 were usual values after 4 

 minutes ionization) they are naturally faint. 



The immediate incentive to the w r ork of the present section 

 was given by the occurrence of elliptic distortions of coronas 

 as shown in the following tables. 



Table 6. — Distorted coronas. Increasing times of exposure to X-rays. 

 dp = 17 cm . Coronal center 19 cm (A-side) and 46 cm (B-side) from bulb. 

 Angular aperture <p = s/30. 



Time 2 min. 



Side 

 First ex 

 Second 



haustion, 



A 



s ■==- 

 s = 



4-5, 



:2'7, 



elliptic, 

 circular 



strong 



B 



1-0? 

 2-4 



faint, circ 

 circular 



mlar 



First 



u 



s = 

 s = 



4-6, 

 4-6, 



elliptic, 



strong 



a 



o-o 

 o-o 







Table 7. — Preceding table continued. 

 Time 1 min. 2 min. 3 min. 



Side ABA B A B 



s= 31, round, 4*1, elliptic, 5*8, ellipse, larger 

 strong strong and distorted 



On second exhaustion, after refilling with filtered air, the 

 coronas were nearly identical on both sides. 



A series of observations was now systematically carried out, 

 unfortunately with somewhat weaker radiation. After 1, 2, 

 and 3 minutes of exposure, respectively, the coronas on the 

 A-side were round to roundish (cf. figs. 1 and 2), of gradually 

 increasing strength and density, and with rainy precipitation 

 and fog usually marked. There was nothing on the B-side 

 even after 6 minutes of exposure. 



