90 Barus — Geometric Sequences of the Coronas of Cloudy 



nize it, if the sequence of colors were not known, from the 

 steam jet. Nevertheless, the march of the axial colors into 

 bluish, greenish, yellowish tints, corresponds to a march of the 

 field from yellows into reds and purples. The colors thus fol- 

 low each other around the circle, apparently diametrically 

 opposed in position. I have stated that the axial yellows, 

 browns, etc., of the first order were not obtainable in any case, 

 directly. 



I made many attempts to strengthen the axial colors by 

 polarized light. The results, though not' negative, are not 

 easily interpretable. Thus the purple of the second order 

 passes between crossed nicols with immensely increased satura- 

 tion. But whether the depolarization is produced within the 

 drum or at the glass windows (which cannot be kept quite 

 clear), or is the result of diffused light entering from elsewhere, 

 I have not been able to determine. These results were par- 

 ticularly marked for columns of about one meter in length. 



If the colors for the drum and for the globe be compared 

 for the same axial flame color, the latter will be seen to be 

 about three orders in advance of the other. This is referable 

 to the greater initial nucleation in case of the globe where the 

 exhaustions were greater. It implies, however, that the initial 

 distribution was in all cases undersaturated, if indeed saturation 

 can here be expected, Apart from this, the nuclear ratio is 

 about the same in the two cases so far as can be made out. 



There is a final outstanding observation of some importance 

 which needs mention. In studying the time losses I noticed 

 that after long waiting (144 min.), single exhaustions seemed 

 to remove two orders of coronas. Similarly on allowing the 

 apparatus fully nucleated to stand over night (say 17 hours), 

 the first exhaustion next morning showed a faint small but 

 definite corona of the ordinary kind, but on refilling with fil- 

 tered air, the subsequent exhaustions produced no corona what- 

 ever. These results can not be associated with the spontaneous 

 production of nuclei from benzol, for instance. The subject 

 requires further investigation. Water is found to produce 

 nuclei after shaking, and it may be that an electrical influence 

 is at work; but if fresh and at rest, the air above it is usually 

 pure relative to such exhaustions as are here in question. 



9. T'ime losses. — Some conclusion must be derived as to the 

 nature of the time loss, which in the above equation has been 

 very fully reproduced (apart from the inevitable errors) by 

 JV= N a y b \ where N is the number of particles per cub. cm., 

 surviving in the receiver after the lapse of time, t: y = *825, 

 o = 'l by experiment. Thus on reduction, if (3 — '0083, 

 N=N^-PK (1) 



As in my preceding papers, I will suppose that the absorp- 

 tion velocity of the nucleus is h cm./sec, independent of the 



