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PRACTICAL MICROSCOPY. 



An ordinary microscope and photographic camera, as 

 shown in Fig. 193, is all that is absolutely required for this 

 work, though with some it may be more convenient to use 

 the apparatus illustrated by Figs. 192 or 195. 



The camera proper is made to remove from the base- 

 board, but this is for portability only. The base-board 

 should project for some distance in front of the camera to 

 carry the microscope and illuminating apparatus as in Fig. 

 193, so that the whole may form a solid continuous base. 

 This is necessary, as well as a good firm table upon 

 which to place the apparatus, and this must be quite free 

 from any vibration to insure perfect sharpness of the 

 image. 



Of course the length of the base-board and of the camera 

 body when extended must vary with the amplification re- 

 quired. The diameters to which an object is enlarged in 

 the camera (Fig. 192) when the sensitive plate is at a distance 

 of 36 inches from the object, may serve as a guide in this 

 direction. 



If the operator prefers to work with the eye-piece in 

 addition to the objective, the camera need only be a 

 short one, say extending from four inches to twelve, the 

 apparatus being arranged as shown in Fig. 193. At this 

 latter distance he will get the same degree of amplification 



