CAMERA-LUCIDA. 2O/ 



A diagram of this form is shown in Fig. 190, from which 

 the reader will see that it consists of a prism of nearly 

 rhomboidal form placed with one of its inclined sides over 

 the eye-piece of the micro- 

 scope. To this is cemented 

 a segment of a small glass 

 cylinder, constituting the com- 

 plete apparatus. This enables 

 sketches to be made with the 

 microscope body disposed 

 vertically with the greatest 

 ease, as although the ordinary 

 camera-lucida or neutral tint 



reflector can be used with the 



FIG. 190. 

 microscope in this position, 



still drawing from it in this way is not a comfortable 

 operation. 



A camera-lucida somewhat similar to the above is made 

 by Mr. Swift and shown in Fig. 191 ; it can also be used at 

 any inclination of the optical tube of the microscope. 



There is another method by means of which microscopic 

 objects may be faithfully delineated, and that is by photo- 

 micrography. This art is usually con- 

 sidered a difficult one, and when we are 

 confronted with the fact that nearly all 

 who have written anything upon the 

 subject have advised the use of a host 

 of complicated paraphernalia, it is 

 scarcely surprising that such an opinion 

 should have gained ground. The vast 

 array of apparatus, condensers of peculiar construction, 

 blue cells, heliostats, and even to a special room set apart 

 for the camera alone, must have been quite sufficient to 

 frighten any one with only their evenings at leisure. 



