108 PROCEEDINGS OF SOCIETIES. 
Messrs. Crisp, Ingpen, Jones, Loy, Ward, Brooke, Bevington, McIntire, 
and Palmer. 
The Chairman announced that it was necessary to elect two gentle- 
men as auditors of the Society’s accounts, and requested the Fellows 
to nominate them accordingly. Mr. B. D. Jackson was then proposed 
by Mr. Bevington, and seconded by Mr. Thomas Palmer; Mr. Gay 
was also proposed by Dr. Gray, and seconded by Mr. Curties. 
The Chairman having put it to the meeting, declared Mr. Jackson 
and Mr. Gay to be duly elected auditors. 
Dr. Wallich read a paper “On the Development, Reproduction, 
and Surface Markings of Diatoms,” the subject being illustrated by 
large drawings upon the black-board. (The paper will be found 
printed at p. 61.) 
The thanks of the meeting were unanimously voted to Dr. Wallich 
for his paper. 
Mr. J. W. Stephenson read a paper “ On some Experiments Illus- 
trating Professor Abbe’s Theory of Microscopic Vision.” ‘The experi- 
ments were exhibited under the microscope, and illustrated by drawings. 
(The paper is printed at p. 82.) 
The Chairman, in proposing a vote of thanks to Mr. Stephenson 
for his paper, said that it appeared to him that these experiments 
clearly showed that diffraction spectra might be produced which 
presented all the appearances which they were accustomed to see 
when looking at a diatom; but it did not appear to be a conclusive 
argument that these appearances might not also be real when pro- 
duced by diatoms, and certainly it did not appear to be a necessary 
consequence that therefore the diatom’s appearance falsely represented 
its structure. 
Mr. Stephenson said that Professor Abbe would quite agree with the 
Chairman’s remarks; the appearances might be true, or might not; 
they left the matter quite undetermined. 
Dr. Wallich said there was only one point on which he should 
like to make an observation. He thought the first thing to be decided 
was what these diffraction images really were. When a diatom was 
properly illuminated, and when they could show it and show it again 
just as they ought to sce it with different powers, it seemed to him like 
reality. The first thing he should like to know would be what 
amount of diffraction was sufficient to define a line ? 
Mr. Stephenson said that the diffraction images of which Professor 
Abbe spoke were produced by the structure examined, and appeared 
in the tube above the back combination of the object-glass. 
Dr. Wallich said he was taken some years ago, by their dear friend 
the late Rev. J. B. Reade, to Dr. Pigott’s to see some diffraction 
images, but they all seemed to him like a confused mass of things, 
and not at all clearly defined or in any way resembling lines. 
Mr. Ingpen mentioned that in the case of Nobert’s bands, the 
diffraction lines were as perfectly clear and sharp as those of the 
bands themselves. 
Dr. Lettsom said that the images shown by Professor Abbe were 
perfectly clear, and those lines could be seen as distinctly and clearly 
