tea:n'sit of tekus. Ill 



Yenus was nearly all off the sun's disc, and one minute before 

 last contact. Taking all these facts into consideration, I cannot 

 see any cause sufficient to account for a ring of light such as that 

 described as seen about the planet, but an envelope of some 

 perfectly translucent substance, such as water. And it is to be 

 hoped that those who used the spectroscope in the northern 

 hemisphere were fortunate enough to get the spectrum of the 

 halo, and settle this question. 



Of the valuable series of photographs which we have obtained 

 little can yet be said. They must all be subject to careful 

 measurement with a micrometer made for the purpose, before the 

 results can be pronounced. And probably twelve -.or eighteen 

 months will elapse before all the results of the world can be 

 combined so as to settle the question of the sun's distance. 



Some, however, of our Janssen plates give results which are 

 obvious enough without measurement ; one of these is the 

 extreme sharpness of all the cusps, even at the very time when the 

 black drop should have had full power over them. Of the sixteen 

 plates, having about sixty photos on each — the first plate shows a 

 small notch in the sun's limb ; Nos. 2 and 4, planet still further 

 in ; No. 5 is the one taken when the black drop was seen ; 

 No. 6 shows the planet wholly within at ingress ; 7, 8, and 9, the 

 same at egress ; No. 9| shows the planet on the sun's limb, with 

 halo ; No. 10, planet partly off sun, with some pictures of the 

 thickening of the ring of light about the pole of the planet ; 

 Nos. 11 to 16 plates, at egress ; No. 17 was passing through 

 when last contact was observed, and shows the faintest notch in 

 the sun's limb till within a few seconds of observed last contact. 

 The value of these plates is very great ; photography is not 

 biased by preconceived theories of what it should see, and is 

 therefore a witness upon questions of physical aspect whose 

 evidence no one may gainsay. 



[Five diagrams.] 



