74 



SUMMARY OF CURRENT RESEARCHES 1! ELATING TO 



being carried by means of the stage micrometer screw, so that the ex- 

 treme edge is exactly on the eye-piece line. The eye-piece can be rotated 

 for vertical measurements. For measuring screws a divided circle is 

 fitted to the top of the body tube, so that by rotating the eyepiece, and 

 reading on the divided circle in conjunction with the stage movements, 

 the diameter, angle, and depth of cut can be exactly ascertained. 



Fig. 8. 



Leitz' Double Microscope.*— C. Metz describes this apparatus, which 

 has an optical equipment essentially different from other forms of appar- 



* Zeitschr. wiss. Mikrosk., xxx. (1913) pp. 188-91 (2 figs.). 



