QUEKETT MICROSCOPICAL CLUB. 387 



graph of Sertularia showed on the screen all details, and was, 

 of course, an exactly truthful representation, while the drawing 

 made with the camera lucida was very much less satisfactory in 

 many respects. 



A series of lantern views of about 100 photomicrographs was 

 then thrown on the screen ; they were drawn from nearly all 

 classes of microscopic work — insects, pond life, botanical subjects, 

 marine objects, geology, histology, diatoms and foraminifera 

 being all copiously represented. The particular point which Dr. 

 Rodman desired to emphasise — viz. the possibility of obtaining 

 a very considerable depth of focus, giving a marked stereoscopic 

 effect — was distinctly evident in many examples in all classes. 

 Some diatom slides exhibited this feature excellently, and formed 

 most beautiful objects, with depth, and yet great sharpness of 

 detail. A slide of Heliopelta, and several strewn slides of perfect 

 specimens, may be particularly noticed. Foraminifera, of course, 

 illustrated this special feature extremely well, as did many 

 botanical objects, some slides of pollen being noticeable amongst 

 them. Especially effective were photographs of various plant 

 hairs, the stinging-hairs of the nettle, and hairs on leaves of Rosa 

 rugosa, Onosma alba, Pelargonium and Sage, among others, stand- 

 ing out with stereoscopic distinctness. 



At the conclusion of the exhibition the President said Dr. 

 Rodman had put his arguments in favour of photography before 

 the meeting very effectively. His own view was that either 

 method was a means of collecting facts, and it was evident that 

 it would have taken anyone a very long time to depict the objects 

 by means of the camera lucida. At the same time, the camera 

 lucida is a valuable instrument. In fossil botany, for instance, 

 the student very often has to work with very imperfect material, 

 but by using a camera lucida he gets the proportions correct, and 

 constructs his drawing by combining facts which have been 

 brought before him by various specimens. He suggested a vote 

 of thanks to Dr. Rodman for his interesting communication, which 

 was heartily given by acclamation. 



A paper by Mr. C. F. Rousselet, F.R.M.S., " Further Notes on 

 Collecting and Mounting Rotifera," and one by Mr. W. M. Bale, 

 " On Measuring the Magnifying Power of the Microscope, a 

 Simple Method," were, owing to shortness of time, read in title 

 only. 



