308 TROUBLES WITH MICRO-PROJECTION [Cn. IX 



For micro-projection the microscope is placed in line with the objective for 

 opaque objects, the objective serving as a condenser. The light passes directly 

 from the radiant through the first element of the condenser and the objective 

 for opaque objects to the microscope. The microscope is so hinged that it can 

 be turned aside and the other forms of projection quickly brought into use. 



6. There may be mist on some of the glass surfaces as the water- 

 cell, or some glass surface like the objective front may be 

 dirty. 



437. Unequal illumination of the screen. This is often due 

 to the lack of centering of some element. 



1. It is usually the crater of the upper carbon that gets out of 



the axis. It is easily corrected by means of the fine adjust- 

 ments of the lamp (fig. 3). 



2. There may be some less transparent part of the object over 



part of the field. One can easily determine this by moving 

 the specimen slightly. 



3. Part of the mask ( 384, fig. 143, 148) may be in the field. 



FIG. 1 73. BAUSCH & LOME'S SIMPLEST FORM OF PROJECTION MICROSCOPE. 

 (Cut loaned by the Batisch & Lomb Optical Co.). 



This is designed for low power projection and consists of an objective holder, 

 rack and pinion focusing adjustment, stage and substage condenser for low 

 powers. The whole is put in place of the projection objective for lantern slides. 

 This simple outfit added to the magic lantern enables one to do very successful 

 micro-projection. 



438. Hazy images may be due to direct light on the screen 

 from some window, etc. Keep especially in mind also that internal 

 reflections in the objective, the microscope tube or the amplifier 

 tube will cause hazy images (370, 371), also dirt or balsam on the 

 front lens of the objective. 



