45 



contained four plates, and he was informed the second would 

 not be long before it appeared. 



A special vote of thanks to Prof. Cleve for his valuable 

 donation was unanimously passed. 



The President said he had also received from a friend — Mr. 

 Marryat — two beautiful series of photomicrographs of Karyo- 

 Kinesis in Lilium bulbiferum. These were all taken by cheap 

 leuses with peacock-blue glass screen, the sections beiug stained 

 with blue haematoxylin. 



The President said that he wished to make a remark with 

 regard to a note of his which was read on March 16th last. In 

 that note, in which he had made no claim to originality, he had 

 referred to common optical formulae, which could be found on 

 the first page of elementary text-books on the subject ; but the 

 alternative formula (vi.) was, so far as he knew, not given in 

 any text-book, and, therefore, might have been considered 

 original. Last night, however, while searchiag some back 

 volumes of the "R.M.S. Journal " for a reference on a totally 

 different subject, he came across the same formula in a paper 

 by Mr. C. R. Cross in the " M.M. J.," 1870, Vol. iv., p. 149, 

 and in the " Journal of the Franklin Institute " for June, 1870, 

 p. 401. So that to Mr. Gross must the honour be accorded for 

 first publishing this simple and very useful formula. 



The President said he had lately come across an article 

 exhibited in a tobacconist's shop as a pipe cover. It was an 

 iris diaphragm, which might be used for cheap microscopes. 

 He had brought it to the meeting for inspection. 



The Secretary said that at their last meeting Mr. Swift 

 exhibited a little portable pond drag which could be carried in 

 the pocket. Since then Mr. Allen had suggested a further 

 improvement by adding a cap to one end to which an eye was 

 fixed, so that a piece of string could be attached. 



The President exhibited and described a new device which 

 he thought might prove of service in microscopical work. It 

 was an addition to the principle of Beale's neutral tint reflector, 

 which, though possessing great advantage over the Wollaston 

 camera or the Soemmering mirror, had the disadvantage of 

 exhibiting the picture laterally inverted. By means of a second 

 lateral reflector this inversion was got rid of and the image 

 appeared erect in both directions. 



