CAMPANULATE CORONAS. 7 



A series of observations was now systematically carried out, un- 

 fortunately 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. 2 and 3), 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. After 

 4 minutes (cf. fig. 4), the corona became spindle-shaped, ^=5.4 cm. 

 in major axis, accompanied by rain from horizontal layers of fog. 



5 

 FIGS. 2-6. A succession of distorted coronas. 



After 6 minutes of exposure to the X-rays, the coronas underwent 

 remarkable distortion, becoming gourd-shaped (fig. 5), often with a 

 long, serpentine neck dipping into the B side of the condensation 

 chamber. The length of figure on the goniometer was about 6.8 cm., 

 the outline being orange and the field within greenish. Rain and fog 

 abounded. The coronas on second exhaustion (after adding filtered 

 air) were green-blue-purple, ^ = 4.9, n = 42,000, and white-red-green, 

 5 = 4.5, n 32,000, on the A and B sides, respectively. The experi- 

 ment was repeated, with like results. 



After 8 and 1 1 minutes of exposure, both the A and the B sides 

 became the seat of the now wedge-shaped corona (cf. fig. 6), greenish 

 within and orange in outline. There was much rain and fog. 



Figures 2-6 are seen immediately after the exhaustion. A moment 

 later there is a storm-like disturbance in the condensation chamber, 

 accompanied by rain and fog. Hence the distribution of nuclei found 

 on exhaustion is incompatible with a persistent distribution of fog 

 particles. In fact, the first coronas usually fall out rapidly, showing 

 the occurrence chiefly of large fog particles in spite of the corona. 

 The second coronas are circular and persistent, whence a nearly uni- 

 form distribution of nuclei may be inferred. 



9. Symmetrically graded sizes or numbers of fog: particles. Since 

 the coronas obtained all show an unmistakable tendency to horizontal 

 symmetry with reference to the longitudinal axis of the condensation 

 chamber, the nuclei to which the coronas are due must either origi- 

 nate in, or else be absorbed by, the top and bottom of the apparatus. 

 Nuclei originating or lost at the front and rear faces are nearly 

 uniformly distributed normal to the line of sight and produce circular 



