INDEX 



163 



Wet collodion plates, faults in, 41 



plates, intensification of, 41 

 Working directions for mixed jets, 6 

 Wray's photo-achromatic lenses, 78, 79 



z 



Zeiss apertometer, 88 



apochromatic lenses, 135 



Zeiss microscopes, how to clean the fine adjust- 

 ment, 72 



models for microscope to be used in photo- 

 micrography, 68, 69 

 photo-micrographical horizontal table, 52 

 " Planar " lens in photo-micrography, 18 

 test plate, 84 

 vertical table, 57 

 Zirconium limes, 1 1 



Printed by Ballantyne, Hanson 6^ Co. 

 t^ondon St' Edinburgh 



