84 THE A B C OF PHOTO MICROGRAPHY 



as in preceding example (Fig. 20); radiant, 

 acetylene i foot burner; exposure, i minute; 

 developer and amplification the same. Ob- 

 serve again another great reduction in length 

 of exposure, due entirely to the lens and its 

 very wide aperture. 



Bacillus Trommel-Schladgcl. Fig. 22. In this 

 final example the optical arrangements were 

 precisely those used with the two preceding 

 ones (Figs. 20 and 21). One screen only, 

 picric acid, was employed, an acetylene i foot 

 burner was the radiant and the plate was 

 slower, being a Forbes' orthochromatic L, in 

 consequence of which, and the denser stain- 

 ing of the subject, exposure was doubled, 

 2 minutes, development and amplification 

 being the same. 



Having carried my readers through the 

 processes of Negative Making from widely 

 differing subjects and illumination ; under low, 

 medium and high magnifications, it remains 

 only to describe very briefly a method of 

 doing the same with still lower powers less 

 than ten diameters. Macrographs such pictures 

 would really be, and I have ventured to coin a 

 word in this connection and call the process 

 Photo-Macrography. Before doing so, however, 

 I deem this a fitting place in which to give 



