﻿Quantum Theory of Photographic Exposure. 961 



manifest from Fig. 2, curve marked N. After exposure and 

 development the clumping of the survived grains was 

 determined all over again and is represented by the curve 

 marked N — K; the curve marked K is the difference of 

 these two curves and represents the clumps affected by light. 



Fig. 2. 

 W12C CLUMPING CURVES 



N=OFHGINAL CLUMPS PER SQ. CM. ONE LAYER PLATE. 

 K= AFFECTED CLUMPS PER SQ.CM. OH E LAYER PLATE. 



N-KsRCMAIHING CLUMPS PER SQ.CM. 



■ =|_£-0493B 



S2000 



1 



0.17 



2 



0.41 



3 



0.68 



4 



0.66 



S 



0.S5 



a 



1.00 



7 



(.00 



uaecn or grains 



3 M>0< f^\" 



TO II 

 szT.ATil 

 II 



Fisr. 3 a. 







Fig. 



3 6. 







• 

 • 



••• 



• 



•• 



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• • • 



• 



• 



• 



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f 



t 



* • 



* * 



• 



• 



'•*.'* 



I . 



t * m ' 



« 







This would suffice perhaps by itself to show that our clumps 

 behave as photographic units. But additional evidence is 

 afforded by figs. 3 a and 36, in which all the individuals were 

 carefully blackened by hand on a microgram originally 

 enlarged 10,000 times ; the former of these figures refers to 

 the original unexposed one-layer grains, and the latter to 



