6 PHOTOMICROGRAPHY 



which combines in itself the features of the last two 

 groups of cameras. The reflex mechanism is contained 

 in a separate segment that can be attached to the rest 

 of the camera, or dispensed with at will, leaving an 

 ordinary hand and stand camera. 



The most generally useful size for the camera is half 

 plate (6J"x4f"), or its American or Continental equiva- 

 lents, but quarter plate (4J" x 3J"), or better, 5" x 4", or 

 9 x 12 cm., is usually quite large enough. The 5" X 4" has 

 an advantage over the others in that its shape is better 

 proportioned to include a circle without waste. Larger 

 cameras than half plate are seldom required, but 10" X 10" 

 or 10" x 8" are often used on specially built outfits, and 

 are very useful for enlarging purposes as well as photo- 

 micrography ; the dark slides of the larger sizes should 

 be fitted with adapters to take the smaller plates down 

 to lantern-slide size (S^xSJ") and 3J"x2J".' 



Adaptation of an Ordinary Camera. Fig. 1 shows a 

 method of fitting up an ordinary half plate camera. The 

 baseboard is of well-seasoned wood 4' x 9" x 2", with a 

 groove iV' broad down its centre. Suitable blocks are cut 

 to carry each component of the system, and strips of hard 

 wood about J" deep are let into them along their centre 

 line ; about " of these projects and slides in the base- 

 board groove. The blocks may warp if not of well- 

 seasoned wood ; their thickness is very carefully adjusted 

 so that the optical axes of the camera, microscope, and 

 lamp may be in line. The microscope carrier is first 

 made, and depressions cut in it to receive the foot of the 

 microscope, and to hold the latter so that the tube lies 

 truly along the centre line and perfectly horizontal. 

 If the microscope will not stand steadily when the tube 

 is horizontal, some means must be taken to support 

 it. A clamp or wooden turn-button pivoted between 

 the horseshoe serves very well, and if nothing better is 

 at hand a temporary support may be made by placing 



