ZOOLOGY AND BOTANY, IMICROSCOPY, ETC. 



425 



made of two pieces of brass stripping fastened on each side of the pillar 

 with a thumb-screw. The lamp is a small tungsten bulb set in a 

 porcelain socket. The shade or reflector, shown in the photograph, was 

 taken by an old tubular flashlight. A small three-cell pocket battery 

 furnishes the current, which is controlled by a push-button at the left 

 of the Microscope. The same battery has lasted for very nearly a year 

 now without visiljle signs of weakening. 



The fan shown in lioth photographs is a toy motor equipped with a 

 4^-inch blade. The motor is operated on two dry cells. It is fastened 

 to a wooden base that is inserted in a slot in the upright and clamped 

 tight l)y means of a winged nut. This fastening permits the fan to be 



Fig. 32. 



tilted up and down, while the single screw securing the fan to the base 

 allows a left and right rotation. The air current may thus be directed 

 on any spot desired. 



Operation. — For Microscope illumination with this dark room a 

 concentrated filament Mazda frosted globe is used. This globe is 

 placed behind the slit in the central curtain, and the Microscope is put 

 in position on the opposite side. The flap covering the slit is then 

 snapped about the tube of the Microscope just above the nose-piece. 

 The slit through which the light comes is so narrow that the stage of 

 the Microscope effectively shields the eye from the light coming through 

 the lower part of the slit, wliile the flap takes care of all other dispersion. 



Aug. 16th, 1916 2 G 



