68 THE A B C OF PHOTO - MICROGRAPHY 



substage, and the ocular is a Huyghenian 

 i%-inch. This is not an ideal photo-micro- 

 graphic combination, but quite equal, no 

 doubt, to those with which many workers will 

 have to be content. Let us see what we can 

 do with it. The operations of centering light 

 and object and of focusing, being precisely 

 the same as those already described, it is un- 

 necessary to repeat them. The plate is an 

 ordinary landscape one of moderate speed. 

 A cobalt blue screen renders the illumination 

 fairly monochromatic in that actinic color, and, 

 of course, does not necessitate prolonged ex- 

 posure over that requisite for the ordinary yel- 

 low rays of the lamp. Still it must be con- 

 fessed that the lighting, as seen on the screen, 

 is not very brilliant, and a somewhat lengthy 

 exposure is deemed necessary. We decide 

 upon five minutes, and it is given. Fortu- 

 nately it is evening; there are no passing ve- 

 hicles, and not a tremor is perceptible through- 

 out all that while. Now comes the develop- 

 ment in eiko-hydro, and we have a negative 

 which I think we need not be ashamed of, in 

 view of the circumstances under which it was 

 made. A reproduction v/ill be seen in Fig. 9, 

 the amplification being 315 diameters. 



A second negative might as well be made 



