324 



" Journal of the E-oyal Microscopical j t th-" i. 

 Society" I n xc ange. 



"Annals of Natural History " ... Purchased. 



" Ray Society's Yolume for 1891 " ... 



" The Essex Naturalist " The Editor. 



The Secretary said they had also received a small donation 

 of some interest from Mr Kitton — a slide of section of shell of 

 Chiton, which was one made by John Quekett himself and 

 figured in his " Lectures on Histology." 



The thanks of the Club were voted to the donors. 



Mr. C. L. Curties exhibited anew camera lucida just received 

 from Leitz ; it was in the form of an eye-piece and could be 

 used with the microscope at any angle, the object being seen on 

 a level with the stage. It had the Continental-size tube, but 

 could be made to suit the English instruments if required. 



Mr. Newton asked if Mr. Curties coukl give them any informa- 

 tion as to how it worked. If the image was projected at the 

 side of the stage he should expect that there would be a very 

 great deal of distortion. 



Mr. C. L. Curties said there always would be a slight distor- 

 tion with any form of camera lucida, but a great deal might be 

 done to obviate that by keeping the plane of the j)aper at right 

 angles to the direction of vision. 



Mr. Michael did not think that under any circumstances could 

 they avoid distortion with a contrivance of this kind unless they 

 drew upon the inner surface of a bowl, otherwise the amplifi- 

 cation must always be different in the centre and at the margin 

 of the field because of the difference in distance. The difference 

 was less when Dr. Beale's reflector was used, but with other 

 kinds the edge of the field was more magnified than the centre. 



Mr. Newton inquired if this would be so when the Wollaston 

 prism was used. Would the lines of a stage micrometer be 

 seen distorted in this way ? 



Mr. Michael said this would certainly be the case ; the divi- 

 sions of iIq inch would always be wider apart near the edge of 

 the field when viewed in this way. 



The President said Mr. Michael had stated what was the fact 

 with regard to all these contrivances. The best of them was 

 probably Beale's neutral tint reflector, but it was not suitable 

 for all purposes, because the picture, though inverted, was not 

 laterally transposed. Thus a micro-photograph of printed 



