V 



145 



Sections of a leech Mr. W. M. Holmes. 



Diatoms, Navicula mormonorum ... ... ... Mr, H. Morland. 



Head of tape-worm, Tcenia medio-canaliculata ... Mr. W. Watson. 

 Attendance — Members, 63 ; Visitors, 5. 



January 23rd, 1885. — Ordinary Meeting. 



Dr. W. B. Carpenter, C.B., F.R.S., &c, President, in the 



Chair. 



The minutes of the preceding meeting were read and confirmed. 

 The following gentlemen were balloted for and duly elected members of 

 the Club, Mr. John H. Garner and Mr. Edward C. Bousfield. 

 The following donations to the Club were announced : — 



" Proceedings of the Royal Society " From the Society. 



" Science Gossip "... .., ... ... ... ,, „ Publisher. 



"Science Monthly" „ „ Editor. 



" Proceedings of the Royal Microscopical i 



Society" f » » Societ ^ 



'American Monthly Microscopical Journal"... In Exchange. 

 " American Naturalist " ... ... ... ... ,, „ 



" Pamphlet on Law and Species," by E. Poulson From the Author. 

 " Transactions of the Northumberland and ~i 



Durham Natural History Society "... J " " Societ y- 



Nine numbers " Linnean Society's Journal " ... Mr. Scholefield. 

 Forty-three Type Slides of Oribatides ... Mr. A. D. Michael. 



The thanks of the Club were voted to the donors, and a special vote of 

 thanks to Mr. Michael for his valuable contribution to the cabinet was 

 unanimously passed. 



Dr. G. C. Wallich exhibited and described his condenser, remarking, how- 

 ever, that everything depended upon getting a proper light, and that the 

 gas lamps in the room were not the best for the purpose. 



The President thought it would be better to reserve a critical examina- 

 tion of the apparatus until the end of the meeting, when the large lamp on 

 the table before him would be available for the purpose. He was sure that 

 every worker with the microscope must feel the value of anything which 

 would give an increase in focal depth, as hitherto they had only been able 

 to get it by reducing the aperture of their objectives ; but there was one 

 very curious thing about the Binocular Microscope, that it did increase very 

 greatly the focal depth. He had tried this under every condition, and had 

 always found it to be so. It was to be explained to a certain extent by the 

 binocular prism halving the aperature of the objective. That, however, did 

 not explain it altogether ; because having asked a friend to look through the 

 binocular with one eye only, the prism being in its place, and to focus the 

 objective for what he considered to be a medial distance, on then asking him 

 to open the other eye, the difference in the depth of focus had been at once 

 observed ; indeed, it was considered that the increase amounted to at least 

 five times. He had talked the matter over with his friend, Sir Charles 



