92 THE MICROSCOPE. [J u ty) 



CAMERA LUCIDA AND NEUTRAL TINT REFLECTOR. 



BY ALBERT SCHNEIDER, M.D., MINNEAPOLIS, MINN. 

 From Primary Microscopy and Biology. 



Camera Lucida (Latin, camera an arched roof, and lucida 

 bright). The student should always delineate objects under 

 examination. The image is thereby more firmly fixed in his 

 mind ; besides, it teaches him to observe more closely. He 

 will be surprised to find that he observes things which he 

 would not have noticed otherwise. The camera lucida and 

 neutral tint reflector are contrivances used with the micro- 

 scope in drawing images of objects under examination. The 

 student of average ability can construct the neutral tint re- 

 flector for himself. 



Take an ordinary cover glass, incline it 45° to the eye lens of 

 the ocular, so that the centre of cover glass and centre of eye- 

 piece will coincide ; fasten it in its place by some contrivance. 

 Now, incline the tube of the microscope till it is at right angles 

 to the pillar. The cover glass will refract the image at right 

 angles. The eye, looking down through the centre of the 

 cover glass, will see the image projected on a paper placed be- 

 low on the table. The position of the light and mirror must 

 be changed to produce the proper illumination. Be careful to 

 avoid too much light where you are going to draw. A prime 

 object in drawing is to produce exact representations. Stu- 

 dents should use paper ruled into squares. Place a cover glass 

 ruled in squares on the diaphragm of the ocular ; this projects 

 the image of the squares with the image of the object. By 

 this means very exact work can be done. 



Amplifications and reductions can be made at will. Cut off 

 most of the light from the paper on which the image is 

 projected, so that it will appear in clearer outlines. Get a 

 good, sharp, lead pencil, and trace the outline of the image on 

 the ruled paper. It is well to use a tinted cover glass, as it 

 gives a better defined image. The student will be surprise to 

 find what he can accomplish by this simple means. The cam- 

 era lucida consists of a prism, and is used in the same man- 

 ner as the tint reflector. 



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TAKING CARE OF A MICROSCOPE. 



When through using the microscope, separate the various 

 parts as much as is necessary, and wipe them perfectly clean 

 and dry. with a silk handkerchief or piece of chamois skin. 



