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PROCEEDINGS OF THE SOCIETY. 
Meeting of 18th February, 1891, at 20, Hanoyer Square, W., 
the President (Dr. R. Braithwaite, F.L.S.) in the Chair. 
The Minutes of the meeting of 21st January 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 given 
to the donors. 
From 
Micrometer for recording the thickness of cover-glass, &c. . . Mr. E. Bausch. 
Slides (6) of Recent and Fossil Diatoms Miss M. A. Booth. 
Photomicrographs (12) Mr. E. G. Love. 
do. (6) Mr. W. H. Walmsley. 
Mr. J. Mayall, junr., said that amongst the donations there was 
(1) a screw-micrometer, devised by Mr. Edward Bausch, of the Bausch 
and Lomb Optical Company, and sent to them for the purpose of illus- 
trating a paper reprinted in the current number of the Journal, 
pp. 108-13. The instrument was intended to furnish a ready means 
of measuring the thickness of cover-glasses to the 1/1000 in. or 
the 1/100 mm. In addition to this, Mr. Bausch had also sought 
to make it applicable to the purpose of indicating at the same 
time the proper length of body-tube necessary to be used with various 
thicknesses of cover- glass so as to obtain the best results from the use 
of each of a series of five unadjustable objectives made by the company. 
The various data which the instrument was intended to record were 
printed on the cylindrical part of the drum connected with the micro- 
meter screw. He thought, however, that the idea might be a little too 
ambitious, because it presupposed that there was an absolute uniformity 
in objectives of the same denomination, which in practice it would be 
hardly possible to attain. The idea was, no doubt, good, and the 
instrument was not only very prettily designed, but was — he was 
informed — very inexpensive. As illustrating a point which Mr. Bausch 
believed to be important in practical microscopy, the Society would feel 
greatly interested in being able to add this instrument to their collec- 
tion. (2) They had received from Mr. Walmsley, successor to Messrs. 
Beck, in Philadelphia, some specimens of the photographs produced 
with a simple form of small photomicrographic camera, which were very 
clear and sharp. The idea of making photographs on such small plates 
was first brought out some years ago by a Dublin firm, who made a 
camera in the form of a little box to fit on the end of the draw-tube. 
Mr. Walmsley had improved on that by making his with a bellows body, 
fitting upon an adjustable pillar and stand. (3) Some photomicro- 
graphs had also been received from Columbia College, New York. 
They were chiefly of popular objects, and had been produced with con- 
siderable technical skill. The letter by which they were accompanied 
