210 SUMMARY OF CURRENT RESEARCHES RELATING TO 



monocular Microscope. Then, by moving his head either forward or 

 backward, he cuts off with his pupils the one or other side of the 

 Ramsden disks, and obtains either stereoscopic or pseudoscopic relief 

 instantly. The movement required is scarcely over one-eighth of an 

 inch, and the result is that all the advantages of stereoscopic relief are 

 obtained without sacrificing anything. The result of the movement of 

 the bead is very astonishing ; if objects are being examined which lie on 

 different levels, one point appears either in front of or behind another at 

 will, and the position of the observer's head indicates which is the stereo- 

 scopic or pseudoscopic picture. 



The makers adapt the binocular equipment to several of their well- 

 known stands. 



Watson and Sons' No. 2 Metallurgical Microscope.* — This in- 

 strument (fig. 27) is identical with the same firm's No. 1 model f ex- 

 cept that it has a tripod instead of a horseshoe foot. This variation 

 has been made to meet what is, apparently, a growing preference for the 

 tripod on the part of microscopists. 



(4) Photomicrography. 



Handbook of Photomicrography .$ — This excellent text-book, the 

 work of H. Lloyd Hind and W. Brough Randies, is, as the authors 

 explain, the outcome of a series of articles originally published in the 

 Photographic Monthly, and is intended as an introduction to photo- 

 micrography from a photographer's point of view. The first five 

 chapters deal with the necessary apparatus ; then follow experiments 

 on illumination, including critical light. After this come chapters on 

 low-power and critical photomicrography, colour screens and colour- 

 sensitive plates, exposure, oblique and dark-ground illumination, metallog- 

 raphy and colour photomicrography. 



The last chapters are devoted to development, printing, enlarging, 

 and lantern-slides, and to the use of photomicrography in pathology 

 and medical practice. 



The volume concludes with an appendix of formulae and reagents. 



The work is copiously and extremely well illustrated, and the 

 publishers are to be congratulated on producing this handbook at a 

 very moderate price. 



(6J Miscellaneous. 



Quekett Microscopical Club. — The 495th Ordinary Meeting was 

 held (in .January 27, the President, Prof. A. Dendy, D.Sc., F.R.S., in 

 the ('hair. S. C. Akehurst on " Some Observations concerning Substage 

 Condensers." The opinions of various authorities as regards the use 

 of annular stops were reviewed. Only one phase of the subject was 



* W. Watson and Sons' Special Catalogue : Microscopes and Accessories for 

 Metallurgy, pp. 10, 11. t See this Journal, 1903, p. 87. 



X London : George Routledge and Sons, Ltd., 1913, xii and 292 pp. (44 pis. 

 and 71 text-figs.). 



