ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



257 



(4) Photomicrography. 



Photographing 1 Fossils by Reflected Light.* — L. D. Burling 

 describes a method of photographing fossils by reflected light. The 

 scheme seems to yield excellent results, and may be generally valuable in 

 photographic reproduction. The back of an ordinary enlarging and 

 reducing camera was pivoted so that it would revolve about a vertical 

 line passing through the centre of the ground glass plate, and the rack 

 upon which the specimens are mounted was made to revolve about a 

 vertical line passing through the centre of the specimen. Suitable 

 scales were so attached to both the specimen rack and the back of the 

 camera, that each might be clamped at any desired angle. In practice 

 the specimen is placed in position, the lens is removed, and the relative 

 position of the light and the angular position of the specimen are 

 manipulated to secure the most favourable illumination. (Experience 

 has shown that variations in the intensity of light are necessary to bring 



Fig. 40. 



out the particular features of different specimens, and that tbi> degree of 

 illumination required can best be determined by direct observation 

 through the camera rather than upon the ground glass.) 



In order to eliminate distortion, the back of the camera is then 

 revolved through an angle corresponding to that indicated by the scale 

 on the specimen rack, the lens is replaced, and the specimen is focused 

 and photographed. The best results have been obtained with lenses 

 having a focal length of at least 6 or 7 inches, or long enough to eliminate 

 any errors arising in the adjustment of the camera. 



Fig. 40 is a plan of the camera showing its arrangement. The light 

 used is a screened arc lamp, suspended by a pulley from the ceiling ; the 

 camera stand is movable, and the specimen rack and the back of the 

 camera are each free to move through an arc of 60°. The box-like 

 projection into which the bellows may be compressed has been cut away, 

 to increase the angle through which the back of the camera may be 

 revolved. 



* Amer. Journ. Sci., xxxi. (1911) pp. 99-100 (1 fig.). 



