360 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Leitz' New Binocular Loup.* — This instrument, which was exhibited 

 at the December meeting (1898) of the Royal Microscopical Society,, 

 is shown in fig. GO. The usual principle of the ordinary binocular 

 Microscope is not adopted, inasmuch as that principle involves a 



partition of the beam of 



light proceeding from 

 an object, and a conse- 

 quent diminution of the 

 brightness of the image. 

 But this instrument 

 consists of two indepen- 

 dent Microscopes, just 

 as an opera-glass is 

 formed of two separate 

 telescopes, and the two 

 images are combined 

 by a mental process. 

 The arrangement allows 

 a greater freedom in the 

 choice of objectives than 

 in the ordinary binocu- 

 lar Microscope. The 

 instrument contains two 

 of Briicke's loups, whose 

 fields of view accurately 

 superpose. The eye- 

 distance from the pre- 

 paration-plane is about 

 250 mm., the field is large and flat, and the magnification about four 

 diameters. The binocular loup admits of horizontal and vertical ad- 

 justment, and can be secured in any position by clamping-screws. The 

 fine adjustment is by rack-and-pinion. 



Fig. GO. 



Dowdy, S. E. 



-Sliding Stage for the Microscope. 



English Mechanic, Ixxix. (1904) p. 21S (1 fig.). 



(4) Photomicrography. 



Dowdy, S. E. — Amateur Photomicrography. 



English Mechanic,]xx\x. (1904) p. 172-4 (5 figs.). 



(5) Microscopical Optics and Manipulation. 



Absorption and Emission of Air and its Ingredients for Light of 

 Wave-lengths from 250 /x to 100 /x.f — After describing a photographic 

 vacuum Spectroscope designed and made by himself, with lenses and 

 prism of fluor-spar, and with arrangements for maintaining the same 

 pressure throughout the body of the instrument, as in the Geissler tube 

 (used end on), V. Schaudinn states his results. 



* Zeitsch. f. Ang. Mikr., ix. (Feb. 1904) pp. 291-2 (1 fig.). 



t Smithsonian Contributions to Knowledge, xxxix. (1903) No. 1413, 30 pp., 4 pis. 

 and 10 figs, in text. 



