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PROCEEDINGS OF THE SOCIETY. 
could, recommending him such books as Dallinger’s edition of Carpenter, 
and it was a little surprising to Germans to find that after so short a 
period he had produced before them such a paper as that which had just 
been read — one which he regarded as a very able one, both as to the 
subject, and the manner in which it has been worked out. As regarded 
the value of the method for purposes of research and the determination 
of structure, he was not so well able to judge of the advantages which it 
offered ; that was not the optician’s work, but was a matter which could 
only be judged of after years of work by those who were accustomed to 
other methods as well, and it was rather a matter for them to apply it 
and afterwards to decide on its value. He was sure, however, that this 
method of using coloured screens was in many respects superior to dark- 
ground illumination for the examination of fine structures. 
Dr. W. H. Dallinger said it would hardly be fitting for him to be 
silent when an opportunity occurred of extending a welcome to the 
representative as well as the great active worker of the largest optical 
establishment in Europe, and knowing as they did that Dr. Czapski had 
not only been a co-worker with Prof. Abbe in his unique optical improve- 
ments, but was now carrying on this work as Abbe’s successor — work 
which had been of such inestimable benefit to microscopists throughout 
the world, they had both to thank him for his presence that evening and 
for the remarks he had made, and to express to him their very cordial 
feelings of personal regard. As to the paper before them, it evidently 
opened up a new feature amongst methods of research which seemed to 
promise to be of special utility ; but inasmuch as it was so new to him, 
and he could not quite see how the use of the glass discs could leave 
delicate optical corrections in the objective unaffected, he was absolutely 
unable to give any opinion concerning it, except as to imaginary results. 
He hoped, however, when he had more strength to do so, that he should 
be able to apply it to all the problems which were at present exercising 
his mind, upon which it might profitably be brought to bear. He most 
heartily thanked the reader of the paper for bringing it before them, 
and again expressed the gratification which it afforded the Society to see 
Dr. Czapski amongst them. 
Mr. Nelson could not say much upon the subject as he had not tried 
any of the experiments himself, but he had seen some of the results and 
thought the paper was one which deserved the highest attention, and 
that those who felt so inclined, and had the means, should certainly 
devote some time to the further following up of so promising a subject. 
He quite agreed with Dr. Czapski as to the admirable manner in which 
the paper had been worked out. 
Mr. Conrad Beck said that at so early a stage it was hardly possible 
to express any opinion upon a paper which described an entirely new 
method of analysing the image of an object by means of variously 
coloured component rays, which in a very rough way reminded him of 
an idea suggested some time ago for producing a stereoscopic projection 
by the use of different colours on opposite sides. 
Mr. G. C. Karop said it was rather curious to note that Mr. J. D. 
Hardy, a former Fellow of the Society, had some time * since invented a 
See this Journal, 1883, pp. 126-7, 158-9. 
