PROCEEDINGS OF THE SOCIETY. 
841 
lucidas, to know that their results could always be corrected by tangent 
measurement. 
Sir Walter Sendall said that was so, but then the tangent method 
could not be used unless they could first determine accurately the centre 
of the field. 
Dr. Dallinger thought there could be no doubt as to the value of this 
ingenious contrivance for obtaining measurements within certain limits, 
but he thought it would require a very great deal of care to be able to use 
it successfully with high powers, and this partly on account of its weight, 
if made in brass as the specimen before them. If an apparatus like that 
had to be hung upon the tube of a Microscope used for high powers it 
would be necessary to have it made of aluminium or some other light 
material. 
Sir Walter Sendall said that he recognized the value of this sugges- 
tion, which could easily be carried out as the principle involved was 
susceptible of modification in any way which would tend to increase its 
efficiency. 
The Secretary read part of Messrs. W. J. Chadwick and W. Leach’s 
paper on the “ Leach Lantern Microscope,” at the conclusion of which 
the authors gave a demonstration, showing upon the screen a number of 
polariscope and other objects. 
The Secretary announced that arrangements had been made for 
holding their next Conversazione on the evening of Monday, November 
30th ; they were unable to secure the use of the room for a Wednesday 
evening. 
The following Instruments, Objects, &c., were exhibited:— 
Messrs. W. J. Chadwick and W. Leach Leach Lantern Micro- 
scope. 
Mr. F. Chapman : — Foraminifera illustrating his paper. 
Mr. W. Hutchinson : — Sections of Cotton. 
Mr. E. M. Nelson :—Navicula firma under an oil-immersion 1/12. 
Mr. C. Eousselet : — A new Rotifer, Conochilus unicornis. 
Dr. H. Schroeder : — Photomicrographs of Herr J. D. Moller’s Type- 
Slides of Diatoms. 
Sir Walter J. Sendall: — Measuring Apparatus for Camera Lucida 
drawings. 
New Fellows. — The following were elected Ordinary Fellows: — 
Mr. Henry Crowther, Dr % Algernon W. Lyons, Dr. Frank Alvin Rogers. 
Honorary Fellow : — Dr. Edouard Bornet, of Paris. 
