531 



high-power photographs, takea at consecutive foci from the- 

 white-dot down to the black -dot image, which were much 

 admired. 



At the meeting of the Club held on April 23rd, 1912, Prof. 

 E. A. Minchin, M.A., F.R.S., Vice-President, in the chair, the 

 minutes of the preceding meeting, held on March 26th, were 

 read and confirmed. 



Messrs. Arthur Mead, William Henry Owen and Reginald 

 Ernest Raab were balloted for and duly elected members of the 

 Club. 



The list of donations to the Club was read, and the thanks 

 of the members voted to the donors. 



Mr. C. Lees Curties, F.R.M.S., for Messrs. Baker, exhibited 

 a new It^-Iu, objective of N.A. 0*18, just placed on the market- 

 by his firm. The image of the test-object, proboscis of blowfly, 

 was exceedingly good, both for definition and absence of colour- 

 fringes. An example of the simple apertometer devised by 

 Mr. Cheshire was also exhibited. 



Mr. A. W. Stokes exhibited and described several models and 

 methods of applying electric lighting to the microscope. He 

 said that, usually, the lamp was separate from the microscope 

 stand, so that the slightest movement of either was apt to upset 

 or at least disturb the illumination. He had several contrivances 

 to show which he had found useful. One method was to have 

 a lamp fixed to the body of the stand by a brass arm. The lamp 

 was hidden from the eye by a light metal tube. Once the light 

 was adjusted on the object it remained so. Current could be 

 taken from an ordinary lamp-pendant or wall-plug. If no- 

 company's supply was available recourse could be made to the 

 very convenient small pocket battery, which could be fixed to- 

 its adjustable arm. Such a battery gave four hours' light, at a 

 cost of fourpence, and it was then quite easy to replace with 

 a new cell. In another form the microscope was fixed on a 

 wooden base with a pocket-battery supplied with a switch. 

 This was adjusted as required, and the whole stand could be 

 carried or moved about without altering the illumination. 



A short paper on Proales {Notommata) gigantea Glascott, by 

 Mr. John Stevens, F.K.M.S., was read by Mr. C. F. Rousselet. 



