760 



SUMMARY OK CURRENT RESEARCHES RELATING TO 



MICROSCOPY. 



A. Instruments, Accessories, etc.* 

 (1) Stands. 



Ross' New Micrometric Mechanical Stage.f — This apparatus (fig. 

 159) is adapted for micrometric measurements, and enables the user to 

 ascertain the exact size of an object with any power. In conjunction 

 with a fine-adjustment of known rate, the depth, length and width of 

 metal fractures are measured at one operation. The micrometer move- 



Fig. 159. 



ments depend on slides built into the stage, actuated by milled heads 

 attached to delicate micrometer screws with divided drums read against 

 pointers or verniers. The bearing-points of the micrometer screws press 

 against steel surfaces, and are kept up to contact by spiral springs. 



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

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

 Optics arjd Manipulation ; (6) Miscellaneous. 



t Ross' Catalogue, 1908, pp. 18-19 (1 fig.). 



