( 547 ) 

 PEOCEEDINGS OF THE SOCIETY. 



Meeting of 13th April, 1881, at King's College. Strand, W.C, 

 The Peesident (Pkofessoe P. Martin Duncan, F.R.S.) in the 



Chair. 



The Minutes of the meeting of 9 th March last were read and 

 confirmed, and were signed by the President. 



The List of Donations (exclusive of exchanges and reprints) 

 received since the last meeting was submitted, and the thanks of the 

 Society were given to the donors. 



From 



Duncan, P. M., and W. P. Sladtn. — A Memoir of the Echino- 

 dermafa of the Arctic Sea to the West of Greenland. 

 80 pp. and 6 plates, (-tto. Loudon, 1881) .. .. Prof . P. M. Duncan. 



Kolliker. A. — Entwicklungsgeschichte des Menschen und der 

 Hoheren Tliiere. 2 vols. 1033 pp. and 606 figs. (8vo. 

 Leipzig, 1876-9) Mr. Crisp. 



Smith, J. E. — How to See with the Microscope. 410 pp. and 



33 tigs. (8to. Chicago. 1880) The Author. 



Four slides of kidney and spinal cord of cat (injected) and 3 

 photographs of the embryo of the chick, 21, 36, and 72 

 hours after commencement of incubation (from the Patho- 

 logical Laboratory, Albany Medical College, U.S.A.) .. Dr. W. Hailes. 



Mr. T. Powell exhibited an oil-immersion -|^-inch objective of 

 1*47 num. aperture, the highest aperture that had hitherto been 

 made. 



Mr. Crisp exhibited a movable stage, intended to be clamped 

 upon an ordinary stage (of German construction) ; also a " Butteriield 

 broad-gauge screw " (see p. 301). 



In accordance with the arrangement made at the last meeting, 

 the subject of the Society Standard Screw was further discussed by 

 Mr. J. Beck, Mr. Bevington, Mr. Crisp, Mr. Crouch, and Dr. Millar. 



Mr. Beck insisted upon the necessity of having the stuel plugs 

 and rings to be used as gauges for determining the sizes of tbe top 

 and bottom of the screw to be cut, and the master tap or " hob " for 

 cutting screw tools, which were originally determined upon by the 

 Committee, and contended that the taps and dies now issued by 

 the Society, not being made on the plan originally designed by 

 Whitwortb, were not sufficient for the purpose of establishing a 

 standard. 



Mr. Bevington said that it must be borne in mind that it was not 

 intended that the taps should be used as every-day working tools for 

 cutting the threads, but that they should be kept as gauges from 

 which proper templets could be prepared for ordinary use. 



