600 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



prism can also be rotated round its own axis, vertical illumination with 

 high powers is greatly facilitated. The iris diaphragm, which is mounted 

 in front of the totally reflecting prism, serves for the purpose of exclud- 

 ing stray light. As the body-tube of the Microscope, as well as the 

 stage, can be moved, an extremely wide space between the objective and 

 the stage is available. No screws of the mechanical stage project above 

 the level of the stage, so that the objects can be illuminated with 

 extremely oblique light. The tube is of extra width, to allow the use 

 of very low powers without cutting down the field. An Abbe sub- 

 stage condenser can be fitted to the stage if required. Plate-glass 

 reflectors, as well as mirrors of different diameters for various kinds of 

 illumination, are provided for. 



R. and J. Beck's " Class " Dissecting Microscope. — This is a strong 

 and convenient instrument of great rigidity, specially adapted for use in 

 the laboratory (fig. 66). It is made in mahogany, with a rack-and- pinion 

 focusing adjustment and a double mirror : the sides form substantial 

 hand rests ; the lenses fit into a double-jointed arm, so that a large 



Fig. 66. 



area of surface can be examined ; a glass plate 4| by 4J in. forms the 

 stage, and this can be replaced by an opal or vulcanite plate if required. 

 The length of the instrument is 15 in., breadth 5 in., height to stage 

 5 \ in. A complete set of lenses and achromatic triplets — and also a 

 small compound Microscope magnifying about 30 diam., which can be 

 dropped into the arm for detailed examination of an object — is supplied 

 if required. 



Gaidukov, N. — Die neue Zeisschen Mikroskope. 



[A review of the instruments in Catalogue No. 33, 1906, of Carl Zeiss, Jena.] 

 Zeitschr. wiss. Mikrosk., xxiii. (1906) pp. 59-67 (4 figs.). 



(2) Eye-pieces and Objectives. 



Simple Compensator Ocular.* — A. Pauly points out that a com- 

 pensating ocular suitable for most practical requirements can be easily 



* Zeitschr. wiss. Mikrosk., xxiii. (1906) pp. 38-41. 



