48 ELEMENTARY PHOTO-MICROGRAPHY. 



Commencing with a simple object and the lowest 

 power, we first set up the baseboard, with lamp, 

 microscope, and camera duly placed in position 

 (see fig. 14), but as an object may be photographed 

 either by direct transmitted light, reflected light, 

 and with dark ground or light ground, we will 

 first consider transmitted light and a light back- 

 ground. 



If the reader has tried the simple experiment 

 of getting an enlarged picture on a sheet of white 

 cardboard, as described in Chapter II., he will 

 have no difficulty in obtaining the image on the 

 ground-glass screen of the camera. 



Having placed the object on the stage of the 

 microscope, it is focussed with the A eyepiece, the 

 camera and sliding block having been removed for 

 this purpose. No substage condenser is needed 

 for powers lower than lin., but for higher powers 

 it is indispensable ; therefore, instead of critical 

 light used for high powers, we take parallel rays 

 from the bull's-eye after the paraffin lamp has been 

 set according to the instructions previously given. 

 The eyepiece is next taken out and a piece of white 

 cardboard placed about I2in. away from the end of 

 the body tube to act as the screen, and receive a 

 projected image from the microscope. The disc of 

 light will possibly be found brighter in one part 

 than another. The lamp is moved sideways until 

 the whole disc is equally illuminated, with the 



