Observations of the Transmit of Mercury. 199 



impression ; and, moreover, it can hardly be subjective, 

 for it retained an unchanged position on the disc whatever 

 the position of the eye while examining it. It also 

 appeared more clearly defined, the better the definition, and 

 smaller and more sharply outlined, the more intense the 

 vision. On the other hand, it did not appear to be changed 

 in position by the planet's rotation as seen at last view ob- 

 tained at about 3^ 30°^. 



In searching for appearances of a dark or luminous ring 

 surrounding the planet, every combination of neutral- violet, 

 red, green and purple glass was used, with the only results 

 that with the combination red and purple whose resultant 

 color was red tending to magenta, there appeared, at instants 

 of the best definition, a very faint violet halo extending 

 outward approximately one-fourth the planet's diameter ; 

 but beyond the fact of its being several times seen, nothing 

 could be determined concerning it : the opportunities for 

 viewing the planet through intervals in the clouds being 

 short and widely separated. 



The atmospheric conditions at Helderberg, although un- 

 favorable and threatening at other times, were, during the oc- 

 currence of the contacts, almost unexceptionable, especially 

 so at I and II when the air was peculiarly clear and trans- 

 parent, and, in the immediate proximity to the sun, the sky 

 assumed that intense blackness which could only exist in 

 the absence of vapors and suspended matter in the atmos- 

 phere. Indeed the station seemed to partake of the 

 features characteristic of a point of much higher elevation 

 than the hypsometric observations and the coast survey geo- 

 detic results unite in giving it. The morning of the 5th, 

 after the heavy rain of the day previous, opened clear with 

 heavy banks of cumuli low in the northern and western 

 horizon and the wind brisk from the north-west. 



