202 



EARL W. BENJAMIN 



FlG. 9. LIGHT, AND FRAME FOR HOLDING 

 EGGS, AS USED FOR THE SHADOW PHOTO- 

 GRAPHIC PROCESS 



The wire circle around the light was used early in 

 the work to hold a curtain for preventing reflection 

 of light from the sidewalk. The eggs are shown as 

 they are placed on the film ready for exposure. 

 At the right is shown the frame used for arranging 

 the eggs in their proper positions 



The micrometers were held in a wood- 

 working clamp to prevent error due 

 to expansion which might result if 

 they were warmed by being held in 

 the hand of the operator. 



All eggs incubated for the shape- 

 character studies, or produced by hens 

 in the shape-selection studies, were 

 measured and the data recorded. 



PHOTOGRAPHING THE EGGS 

 FOR SIZE AND SHAPE STUDIES 



It was thought desirable to have 

 some sort of graphic representations 

 of the eggs selected for size and shape, 

 and to compare these with represen- 

 tations of the eggs that the pullets 

 produced during the following year. 

 Photography was the first method of 

 representation considered. Since this 

 was very expensive, however, the 

 practice of allowing the shadows of 

 the eggs to fall directly on sensitized 

 photographic paper was adopted. 6 

 A sheet of sensitized paper, 9 by 11 

 inches in size, is slipped into the 

 back of a specially constructed frame, 

 where it is held securely by a wooden 

 support. The sensitized paper is 

 slipped in back of a sheet of stock 

 film glued in the frame; this film, if 

 kept clean, does not hinder the re- 

 production, .reflects much of the dif- 

 fused light, and thus prevents the 

 blurring of the shadow. 7 



The eggs are placed on the film as 

 shown in figure 9, and are held in 



6 It was necessary to use high-contrast paper for this 

 work, in order to obtain distinct black and white tones. 



7 This stock film is the base used for photographic 

 films before the gelatinous coating is applied. It is 

 transparent. 



