197 



Menelaus he had seen before. The other he had gone over carefully with an 

 oil immersion, but did not get more than Mr. Warren de la Rue had 

 obtained ; but on focussing lower down he fancied there was evidence that 

 the objective gave the image of the lower side as well as of the upper side- 

 Mr. Stokes said, with regard to the statement of " pigment being 

 figment," he might say that a friend of his had been getting the colour out 

 of some of the scales, and he found that the colours obtained differed in 

 various kinds of butterflies and moths. 



Mr. Smith said he had never seen any trace of pigment cells himself, but 

 there were in some instances some little tubes found which possibly might 

 contain something of the sort. The coarser scales were simply composed 

 of one membrane. 



The President said it would, of course, be unfair to in any way 

 criticise or judge of the matter before them without having first 

 examined the objects to which Mr. Smith had called attention ; but, 

 so far as his own observations went, he thought there could be little 

 doubt that in most cases scales were double, and it frequently happened in 

 such cases that one surface gave one image and the other one gave another, 

 the ordinary appearance being the result of a combination of the two. In 

 most cases this was an interference image, just the same as might be pro- 

 duced by placing two surfaces of muslin, or other perforated material, one 

 over the other. A great variety of patterns might be produced in this way, 

 and it had always struck him that many of the patterns on scales were due 

 to this kind of interference. He had also noticed how common it was, that 

 when a person came to ox amine with high powers, surfaces which had 

 previously been supposed to be smooth, he discovered that they were 

 not so. 



The thanks of the Club were unanimously voted to Mr. Smith for his 

 paper. 



The President said that, according to the agenda, a paper by Mr. Lowne 

 was to have been taken next. As, however, their time had so far expired 

 they proposed, with Mr. Lowne's concurrence, to postpone the reading of 

 this paper to their next meeting. 



Mr. Morland read a reply to a criticism in the Royal Microscopical 

 Society's Journal for the current month, on his paper on " Mounting 

 Media, so far as they relate to Diatoms." 



The Secretary announced that he had received applications for assistance 

 of members at the Soirees of the Croydon, and South London Microscopical 

 Societies, both of which, however, were arranged to take place on the same 

 evening. Meetings of the Club for the ensuing month were also mentioned, 

 and the proceedings terminated with the usual conversazione, and the 

 following objects were exhibited : — 



Pelomyxa palustris Mr. F. W. Andrew, 



C amp odea staphylinus Mr. E. T. Browne. 



Hydra vulgaris Mr. H. A. Crowhurst. 



Parasitic fly, Callimome regius J ... ... Mr. F. Enock. 



Section of eye of butterfly, Pieris brassica ... Mr. H. E. Freeman. 



