PLATE 2. 



Photographs at Natural Size or small magnification with 

 ordinary Photographic and Telephoto Lenses. 



A EMBRYO CHICK IN SHDLL after 19 days incubation x 1 



Objective Photographic lens. R.R. 6" Focus. 



Aperture ... ... F. 32. 



Plate Imperial Special Rapid. 



Illuminanl ... Diffused daylight. 



Exposure 2 min. 



Developer ... Pyro-soda. 



The chick was exposed by carefully cutting away the upper part of 

 the shell under water. 



The photograph was taken with the object completely immersed 

 in water; the shell supported on a base of plasticine. 



The black background is a sheet of black paper soaked in 

 methylated spirit previous to immersion in water, to avoid air bubbles 

 rising from the paper. 



FOSSILS x 5i 



B Hoplites laulus from the Gault, Cambridge, England. 

 C Potamides cristatus from the Lutetien, Chambors, France. 



Objective Dallmeyer's "Adon" Telephoto, with extension 



tube. 



Aperture Iris in extension tube closed down to its limit. 



Extension ... Image distance, 19^". Separation of lenses, 5". 

 Plate Wj?:."- ... Schleussner's "Paragon." Fine grain ordinary. 

 Illuminanl ... 4 amp. arc, diffused. 



Exposure B. 2 min. Dark-coloured fossil. 



C. 1 min. White fossil. 

 Developer ... Metol-quinol. 



The fossils were laid on dead black paper and a vertical camera 

 used. 



The great restriction of aperture is necessary to get covering power 

 and depth of focus, as the " Adon" was made for distant objects. 



Photos. W. B. R 



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