1883.] of Venus across the Sun. 319 



I may add that the object -glass of my telescope was made by 

 M. Secretan, of Paris, and is of 3£ inches diameter and 51 inches 

 focal length. It is coated on the inner side with a silver film, 

 which I found was quite sufficient to reduce the brightness of the 

 Sun, when used, as I employed it, with a diagonal eye-piece. The 

 mounting eye-pieces and micrometer were by Mr Simms ; and I 

 can take no exception to any part of the instrument. I un- 

 fortunately did not receive in time an eye-piece, power 120, 

 constructed on the principles which I explained to the Society in 

 October last ; but I am not prepared to say that it would have 

 removed the slight indistinctness which certainly I noticed with 

 the power I actually used, viz. 135, for which I cannot entirely 

 account, but which I am. sure was practically not enough to affect 

 the apparent time of contact, at any rate more than two or three 

 seconds, within which similarly situated observers seldom agree. 

 I saw nothing like an atmosphere round Venus, though I looked 

 carefully for it : it is possible that my telescope, considerably 

 smaller than what I may call the authorized size, would not be 

 large enough to shew it. At the same time it is, as far as I can 

 tell, tolerably achromatic : and I will take this opportunity of 

 mentioning a phenomenon, possibly of a somewhat similar nature, 

 which I have observed here more than once. The Sun could be 

 seen from my place of observation to set behind a ridge of hills 

 perhaps thirty miles distant. When examined with the telescope, 

 at an elevation of about one degree above the horizon the lower 

 limb was of an orange tint, the sides of the Sun's ordinary colour, 

 and the upper limb green : these tints continuing as the two limbs 

 successively disappeared behind the hills, which are often quite 

 free from any cloud or haze. I do not recollect having seen the 

 phenomenon described in any book : nor am I sure of its expla- 

 nation. 



In conclusion I should mention that nothing could be more 

 favourable than the weather throughout the day. In the morning 

 there was no sign of a cloud anywhere : and in the afternoon a 

 few light fleecy clouds floating about did not intercept the Sun's 

 rays at any time when I was actually observing. 



February 12, 1883. 

 Mr Glaisher, President, in the Chair. 



Mr T. H. Corry, B.A., Caius College, was balloted for and duly 

 elected a Fellow of the Society. 



The President referred to the terrible loss that Mathematics 

 had sustained by the death of Professor H. J. S. Smith, of Oxford, 

 an Honorary Member of the Society. In the Theory of Numbers 



