806 



SUMMARY OF CIKKENT IJESEAHCHES RELATING TO 



MICROSCOPY. 



A. Instruments, Accessories, etc.* 

 (1) Stands. 



The Binocular Microscope, f — J. Amann points out that the im- 

 portant developments of late years in Microscope construction leave little 

 hope that much further optical improvement is likely to be made. He 

 thinks, however, that practical and especially hygienic considerations 

 still require attention. He would much like to see the Continental 

 Microscope adapted to normal binocular vision. He contrasts monocular 

 with binocular vision, to the disadvantage of the former, but fully admits 

 the difficulties of the undertaking to which he invites the attention of 



Fig. 87. 



Microscope makers. The latest and most complete binocular is Green- 

 hough's Stereoscopic Microscope, but it is only adapted for comparatively 

 weak objectives, which are quite insufficient for modern biological in- 

 vestigations. He considers that the constructional requirements to be 

 met in designing a binocular arrangement are : — 1. That the arrange- 

 ment should not sensibly alter the correction of the optical system ; it 

 should permit the use of compound objectives— weak, medium, high, 

 including homogeneous immersions. 2. That it should likewise be avail- 

 able for oculars of various types — Huyghens, Ramsden, Compensator. 

 3. That there should be no sensible loss of light ; the light-strength of 

 both fields should be approximately the same. 4. That the arrangement 

 should be easily inserted and removed, in order to use the Microscope 

 monocularly or binocularly as desired. The binocular should be suitable 



* 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 Zeitschr. wiss. Mikrosk., xxvii. (1911) pp. 488-93. 



