53 



f 



the bull's-eye was a mistake. For high powers a lamp was good 

 enough for him, and for a large bright field the flat of the flame 

 would give all that was required. The ordinary bull's-eye had far 

 too long a focus for use with large substage condensers. 



Mr. F. Orfeur said the next best thing as an illuminant was 

 the oxy- hydrogen light but he had lately adopted an inverted 

 gas burner with success, having made an opaque chimney of a 

 piece of brass tube with a |-in. hole drilled in it. 



Mr. M. Blood had spent a great deal of time in experimenting 

 ^s to the best illumination to be obtained, and found that the best 

 was obtained by using the edge of the flame, which gave quite 

 ^ nice resolution but by using a particularly well corrected 

 condenser he found the resolution was very much improved 

 under an apochromat of 1-4 mm. With a bull's-eye they could 

 not have critical illumination, and this might possibly explain 

 why Dr. Reid could find so little difference between the photo- 

 graphs he had shown them. 



Dr. Reid having replied, Prof. Minchin said they had listened 

 with great interest to this paper and had very heartily to thank 

 Dr. Reid for it. 



The thanks of the meeting were unanimously voted to Dr. Reid 

 accordingly, 



Mr. C. D. Soar, FR.M.S., exhibited twenty-one sheets of 

 beautifully coloured figures of water-mites. He said they illus- 

 trated all the recorded species of the genus Arrhenurus found 

 in the British Isles. This genus is the most interesting of all 

 the genera of the Hydrachnidae, and contains over 200 species 

 from different parts of the world. It has the largest variety of 

 forms. The males jare quite distinct in shape from the females, 

 and the last and not least interesting feature is the beautiful 

 ^nd brilliant colouring which they exhibit. Fifty species have 

 been recorded in Britain. 



Mr. F. Enock, F.L.S., etc., was proposed as an Honorary 



Member of the Club, on behalf of the Committee. 



At the meeting of the Club held on May 28th, Mr. E. J. Spitta, 

 L.R.C.P., M.R.C.S., Vice-President, in the chair, the minutes 

 of the preceding meeting, held on April 23rd, were read and con- 

 firmed. 



