8 PHOTOMICROGRAPHY 



the method used for sliding the carriers along the base- 

 board. 



The camera is a large one (10"x8"), with an extension 

 of 26" and a breadth of 11", so that a baseboard 6' x 15" 

 is used. A block to carry the camera is screwed on one 

 end, and fitted with angle -irons at the front ; the camera 

 has a rigid base, so that it can be readily placed in exact 

 position against these, and held there by a screw clamp 

 at the back. 



Two strips of wood about 3' or 3' 6" long, and 1" square 

 section, are bevelled along one edge and screwed to the 

 baseboard parallel to its length, and about 8" apart, 



Fig. 2 



ARRANGEMENT FOR ENLARGING CAMERA 



to form runners between which the carriers for the 

 microscope and illuminating apparatus slide. The carriers- 

 are made of inch-board bevelled to dovetail into the 

 strips, and on them the microscope, lamp, and condenser 

 are fitted as in the first example. 



An ordinary optical lantern with 4" condenser is shown 

 in the figure as the source of light. A cooling trough for 

 water or fluid light-filters is carried in the holder pro- 

 vided for lantern slides. A bull's-eye condenser is also 

 shown, and can be used in conjunction with the large 

 condenser, or in place of the latter ; it is screwed into a 

 tube mount which can be pushed in or out of a wooden 

 holder for focussing purposes. Colour screens and dia- 



