488 SUMMARY OF CURRENT RESEARCHES RELATING TO 



MICEOSCOPY. 

 A. Instruments. Accessories, etc.* 



(1) Stands. 



Binocular Microscopes.— F. E. Ives, F.R.M.S., of New York, has 

 drawn our attention to a form of binocular Microscope which he 

 invented in 1902, which would appear to foreshadow the new types 

 of binoculars now being placed upon the market. Ives' design was 

 described in our Journal/ 1903, p. 85, but it does not appear that it has 

 been placed in the hands of the public. Conrad Beck informs us 

 that he had not seen or heard of this instrument, or he would have 

 included a description of it in his paper on Binocular Microscopes, 

 although his paper was only intended to describe the better known types. 

 The optical design of Ives' binocular consists of a cube of glass com- 

 posed of two right-angle prisms cemented together with a partially 

 silvered surface at their cemented junction, and a right angle reflecting 

 prism on one side to receive the beam of light which is reflected from 

 the partially silvered surface. This right-angle prism is made very 

 thick in order to equalize the optical length of the parts of the two 

 beams in a similar manner to that of the Leitz left-hand prism. f The 

 chief difference between the design of the Ives' binocular and that of 

 the Leitz or Beck lies in the fact that this side prism is provided with 

 an adjustment to vary the angle of the two beams of light which enter 

 the two eyes in order to vary the interocular distance, whereas the angle 

 of the other instruments is fixed and the interocular distance is varied 

 by mechanical means, the prisms being rigidly set so that they are 

 permanently in adjustment. The draw-tubes of the two eyes in the 

 Ives' instrument are not connected, and to adjust the tube-length each 

 tube is pulled out separately, presumably to some fixed scale on each 

 tube. 



C4) Photomicrography. 



Scheffer's Mirror-reflex Camera for Photomicrography ; Scheffer's 

 TJicroscope-table for Subjective Observation and Photography, t— 

 In 1909 E. W. Scheffer described § the original form of his mirror-reflex 

 c.imera. His experiences with the apparatus have suggested certain 



* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) 

 Illuminating and other Apparatus; (4) Photomicrography; (5) Microscopical 

 Optics and Manipulation ; (6) Miscellaneous. 



t See this Journal, 1914, p. 7, pi. 1. 



J Zeitschr. wiss. Mikrosk., xxxi. (1914) pp. 84-96 (6 figs.). 



§ See this Journal, 1909, p. 648. 



