PROCEEDINGS OF THE SOCIETY. 647 



(so to say) the red and blue rays at the margin of the object-glass was 

 not somewhat similar to the effect i^roduced in the eye-piece of the 

 telescope by making the red and blue rays cross over. 



Professor Abbe said that there was a certain similarity, but there 

 was also a considerable difference. He then further explained by means 

 of drawings the course taken by rays departing from different points 

 and passing through the object-glass. 



Mr. lugpen hoped that in passing a cordial vote of thanks to 

 Professor Abbe, they would not omit to compliment him upon having 

 taken a course so very rarely pursued by those who worked at the 

 theory and practice of ojitics; he had not only made a most valuable 

 improvement in objectives, but had at once explained its principles 

 and method of construction. 



Mr. Crisp said that they had to signalize the presence amongst 

 them that evening of an Ex-officio Fellow, elected under the amended 

 Bye-laws — Dr. H. E. Fripp, the President of the Bristol Naturalists' 

 Society — who was, he believed, the first Ex-officio Fellow (not being 

 also an Ordinary Fellow) whom they had yet had the opportunity of 

 w^elcoming. Dr. Fripp had (as he expressed it, — by way of recognition 

 for the compliment paid to his Society) sent tliem a most valuable 

 paper " On the Theory of Illuminating Apparatus employed with 

 the Microscope." The paper was a long one, and at that late hour 

 they could not do justice to it in full, but he would earnestly recom- 

 mend all working microscopists to study the paper when it appeared 

 in the Journal. 



Portions of the paper were then read (see p. 503). 



The President having invited Dr. Fripp to make some remarks, 



Dr. Fripp said that he rose, not to speak about his paper, but to 

 allude to the circumstance of his being present with them on that 

 occasion, no longer as a visitor, but by the courtesy of the Society as 

 one of its Fellows. For this courtesy he desired to show himself 

 grateful in the directest manner which common sense dictated, namely, 

 by accepting the good things which came in his way, and evincing his 

 appreciation by hearty enjoyment of them. But he wished also, 

 as one of the first of the Ex-officio Fellows under the new rule, to 

 add that he thought the step taken by the Society in holding out a 

 hand of fellowshij) and helj) to those at a distance who were working 

 with less advantages to the same end rightly accorded with the true 

 instincts of science and the enlarged spirit of the age. He therefore 

 felt that those who were thus favoured were called upon to make 

 whatever humble return they might be able. 



Mr. Beck much regretted that an opportunity had not been 

 afforded of having a discussion on the subject of Dr. Fripp's paper, as 

 it had a very important bearing on the practical working of the Micro- 

 scope. Just lately a person described to him some very remarkable 

 appearances which he had observed, and he was enabled to show that 

 ttiey were entirely due to a defect in his illuminating apparatus. He 

 thought that it would be well to have a full discussion on the subject. 



The President said that from pressure of time, as they had other 



