278 PHOTOMICROGRAPHY 



Camera. J plate, and Optical bench with focussing 



gear. Or a vertical camera. 

 Lamp. Nernst, limelight, or incandescent gas. 

 Collecting lens. Aplanatic or 4" double convex lens 



and iris diaphragm to fit Optical bench. 

 Colour Screens. Set of nine 2" gelatine squares. 

 Cooling trough. 

 Focussing lens. 



Stops for dark ground and oblique illumination. 

 Davis diaphragm. 



III. Microscope of Group 1. 



Objectives (apochromats and achromats) with Eye- 

 pieces (p. 81). 

 Condensers. Achromatic N.A. 1-0, together with a 



low-power illuminator and oil-immersion condenser. 

 Large Camera and Optical bench completely fitted 



with stands for condensers, iris diaphragm and 



cooling trough. 

 Lamp. Arc, 4-amp. Limelight. Nernst or Mercury 



Vapour. 

 Collecting Lenses. Aplanatic condensers with iris 



diaphragm. 

 Colour Screens. Set of nine 2" gelatine squares 



mounted in optical flats. 

 Cooling trough. 



Stage to fit Optical bench to hold large objects. 

 Focussing lens. 



Stops for dark ground and oblique illumination. 

 High-power dark ground illuminator. 

 Stage and Eyepiece micrometer. 

 Davis diaphragm. 



