502 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



MICROSCOPY. 



A. Instruments, Accessories, &c* 



(1) Stands. 



F. E. Wright's New Petrographic Microscope. t — In the design of 

 this instrument the author adopted the Zeiss No. 1 C as his base. This 

 particular model was chosen chiefly because of its wide upper barrel, 



Fig. 53. 



which was well adapted for the introduction of diaphragms and the 

 movable Bertrand lens. The general view of the new Microscope is 



* 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 Amer. Journ. Sci., xxix. (1910) pp. 407-14 (5 figs.). 



