138 
PROCEEDINGS OF THE SOCIETY. 
Meeting of 20th December, 1893, at 20 Hanover Square, W., 
The President (A. D. Michael, Esq., F.L.S.) in the Chair. 
The Minutes of the meeting of 15th November last were read and 
confirmed — subject to a slight alteration as under — and were signed by 
the President. 
Dr. W. H. Dallinger on the reading of the minutes said that his 
remarks as there recorded on the subject of tube-length scarcely con- 
veyed the idea he had intended. He did not for a moment suggest that 
the Society should be charged with the duty of such a committee, be- 
cause the interest in the matter was world-wide and therefore the 
microscopists of other countries should be equally concerned in it. He 
would therefore like to make a slight modification by substituting for 
the last sentence “ that the whole question should be dealt with by the 
appointment of an International Committee for the purpose.” 
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 
Eleventh Eeport of the State Mineralogist. (8vo, Sacra-) The California 
mento, 1893) / State Mining Bureau. 
E. Lauterborn, UeberBauund Kerntheilung der Diatomeen.) m t , 7 
(8vo, 1893) } The Author. 
4 Photomicrographs ( Trichina spiralis and blood-corpuscles) Dr. W. N. Sherman. 
Slide of Arachnoidiscus Mr. B. W. Priest. 
Mr. E. M. Nelson exhibited and described a new pattern Microscope 
specially designed for agricultural purposes, for the examination of 
seeds, leaves, &c., with low powers (see p. 107). Also a new form 
of metallic chimney for a Microscope-lamp fitted to carry a silvered con- 
vex lens, by means of which a powerful parallel beam of light can be 
projected through the glazed opening on the opposite side (see p. 109). 
Mr. Nelson also, on behalf of Mr. J. W. Lovibond, exhibited some 
new coloured screens for use with the Microscope ; he said that 
Mr. Lovibond, who was unfortunately prevented from coming that 
evening, had for some time past been experimenting with screens for 
microscopical work. 
Screens or light-modifiers were an old invention, but partly owing 
to photomicrography their importance had of late become more fully 
recognized. 
Mr. Nelson, who had for many years been using two thicknesses of 
pot cobalt glass, had received from Mr. Lovibond a piece of flashed 
peacock green. This glass, when used in combination with one thick- 
ness of the cobalt glass, gave better results than any hitherto obtained. 
The red was cut out, and a large quantity of blue passed ; unfortunately 
