106 TEANSIT OF VENUS. 



Messrs. Bellfield and Park, who were observing at Armidale 

 witli a 4i-inch Cook telescope, that I examined and know to be 

 a good one, have sent me a valuable report, and drawings of what 

 they saw, and state that — " "While Venus was advancing at ingress 

 to about one-fourth her own diameter upon the sun, a faint 

 tremulous shading was seen between the limb of the sun and the 

 planet (both bodies being very sharp in outline), which disappeared 

 so gradually that it could not be said to have been obliterated at 

 any particular instant." 



Mr. Bolding, P.M., Raymond Terrace, observed with a 3-inch 

 telescope, and has forwarded to me a very complete report 

 of the whole transit, and remarks : — " At the moment I expected 

 a complete circle {i.e., internal contact) came the apparent pause, 

 instantly followed by a kind of indistinctness which resolved 

 itself into the form of a figure S. The thing seemed to be 

 iioldiug up the planet, so to say. The line seemed blacker than 

 the central spot ; then the light came very distinctly between 

 the planet and the line ; then the indistinctness between the 

 sun's limb and the line cleared up, and for a short time the 

 line was clearly seen midway between the planet and the sun's 

 limb. The sun was very hot at the time and the definition bad." 



At ingress I saw nothing of this phenomenon, but at egress I 

 (did, and my report is as follows : — " At times there were moments 

 of bad definition evidently caused by the clouds then forming in 

 the west. During one of these, at 3h. 53m. 54s., when Venus was 

 less than 2 seconds of arc from the sun's limb, the limb of the 

 planet nearest the sun's edge seemed to be in a state of vibration, 

 as if portions of its blackness were jumping over to the margin 

 of the sun with an appearance similar to sketch (diagram 3), 

 which represents one vibration only. This lasted only a few 

 seconds — the vibrations being estimated at 6 or 7 per second. 

 After this the limbs recovered their perfect definition, and were 

 clearly and steadily separated by a fine line of light." 



Mr. Lenehan saw it, and says — " The first apparent contact was 

 at 3h. 54m. 22s., a little jumping. I afterwards saw a band or faint 

 and narrow streak of light between the limbs of planet and sun." 



Messrs. Belfield and Park saw the same appearance at egress 

 as at ingress. Mr. Bolding saw nothing of it at egress, which he 

 attributed to the increased steadiness of the atmosphere. 



I think there can be no doubt that this appearance was caused 

 by temporary unsteadiness in the atmosphere, which by producing 

 rapid vibrations or apparent motions in the limbs under exami- 

 nation, caused them momentarily to overlap, and so cut off the 

 sunlight and produce the black appearance, an eff"ect which all 

 who have been in the habit of observing stars in powerful tele- 

 scopes will at once understand. 



