1893.] MICROSCOPICAL JOURNAL. 167 



A I)evic«' (o lakr (lie Place of tlir Caiiu'ra Ijicida in 

 Micrography. 



By henry G. FIFFARD. M. I)., 



NBW YORK. 



The art of inicrograpliy, or the reproduction on paper of im- 

 ages of minute objects seen through the microscope, may be 

 practised in various ways, of which the three following are the 

 principal : 



1. The observer studies the object on the slide, and when he 

 thinks iiehas theoutlinesand dctailsor]a portion of them sufHcient- 

 ly impressed on his mind, withdraws his eyes from the tube and 

 commits the mental picture to paper, using, of course, both eyes in 

 directing the movements of his pencil. .Success with this pre- 

 supposes a very retentive memory and considerable skill as a 

 draughtsman. 



2. The observer, looking down the tube in the usual way 

 with one eye (for convenience the left), is, after a little practice, 

 enabled, by a sort of autoprojection, to see an image of the object 

 on a sheet of paper by the side of the microscope. The outlines 

 of this image he traces with the pencil, using the right eye to 

 direct its movements, the observation and the reproduction being 

 simultaneous. 



T,. By the aid of a camera lucida, of which there are many 

 different sorts, a reflected or projected image is visible on the 

 paper with the eye that is at the same time occupied in directly 

 observing the magnified image of the object on the stage. In one 

 of the latest forms of camera lucida — the Abbe — this use of half 

 the eye for observing and the other half for recording is a reason- 

 nably convenient method, if the observer's eye is approximately 

 normal ; marked myopia or hypermetropia, and still more 

 pronounced astigmatism, necessitating the use of spectacles, 

 render the use of the camera lucida inconvenient, if not well 

 nigh impossible. 



Some time since, it occurred to the writer that the practice of 

 micrography could be greatly simplified by adopting the principles 

 employed in ordinary projection, as used in connection with the 

 optical lantern, the projection microscope, photography, etc. It 

 was only a question of reflecting the projected image onto a piece 

 of drawing-paper fixed in some convenient position. To this 

 end, I requested Bausch and I.,omb to mount a right-angled re- 

 flecting prism with a short tube extending from one of its square 

 faces, this tube to be of such calibre that it could be inserted into 

 the microscope in the place of the eyepiece. From the other 

 square face a siinilar short tube extends, capable of receiving the 

 ocular and holding it firmly. 



When preparing to use this device the object is placed on the 

 stage, and focused in the usual manner. The microscope is then 

 brought to a horizontal position, the eyepiece is removed, and 



