MICROSCOPE AND CAMERA ALLIED 



apply it to our camera lens and it will have the 

 effect of shortening its focus. This extra lens can 

 either be fitted in front of our original lens by 

 cutting two inches of cardboard, of such a size that 

 they will just fit into the lens hood. In the centre 

 of each piece of cardboard, cut two circles, slightly 

 smaller in diameter than the diameter of the 

 convex lens. Place the lens over the opening in 

 one of the pieces of cardboard and stick the other 

 piece upon it with glue or seccotine. When dry 

 fix the lens in its cardboard holder in the front of the 

 lens hood and repeat the focussing experiment with 

 the foot rule. We shall now obtain a much greater 

 magnification with the same length of bellows, 

 because the additional lens has shortened the focus 

 of our original lens. Probably our camera is fitted 

 with a double lens and it is possible to unscrew the 

 front portion, in this event our extra lens with its 

 cardboard holder may be fitted inside the front 

 lens up against the diaphragm and the front lens 

 replaced. The result is practically the same what- 

 ever the position of the new lens, but we must be 

 certain that it is convex, for a concave lens would 

 increase the focal length of the whole and so reduce 

 our magnification. 



We may find that the amount of enlargement 

 we can now obtain is sufficient for our purpose; if 

 so we can go ahead and produce photo-micrographs 

 of all the objects we desire. The methods of doing 

 so differ in no way from those employed in taking 

 ordinary photographs and as we are writing about 



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