APPLICATION TO MICROSCOPE. 



picture will be magnified in its linear dimensions, in the exact 

 proportion in which its distance from the camera is increased. 



9. One of the most recent and beautiful applications of the 

 camera-lucida, is its adaptation to the compound microscope, by 

 means of which, details and lineaments of objects, so minute as 

 to escape ordinary vision, are depicted with a precision and 

 fidelity only surpassed by the results of photography. 



The instrument is fixed upon the eye-piece of the microscope, 

 in such a manner, that while the observer looks directly through 

 the eye-glass at the object, he sees the paper and pencil by 

 reflection, the latter being placed upon the table before him. Sup- 

 posing the axis of the microscope to be horizontal, the paper and 

 pencil will be reflected from a plane mirror placed at an angle 

 of 45 with the vertical, the reflecting side being turned down- 

 wards. 



The instrument may be so arranged, that the paper may be seen 

 directly, and the object by reflection. In this case, the mirror is 

 also placed at 45 with the vertical, but the reflecting side is 

 presented upwards. The rays, proceeding through the eye-glass 

 from the object, are reflected upwards and received by the 

 eye of the observer, which, looking downwards, views the paper 

 directly. 



In figs. 6 and 7, is shown the arrangement by which the observer o, 

 views the object directly through a small hole in the oblique 

 reflector, which is fixed upon the eye-piece, while he sees the paper 

 and pencil by two reflections, the first from the back of the prism p, 

 and the second from the oblique reflector M m. The effect is to 

 project the image of the object seen in the microscope v, upon the 

 image of the paper seen in the reflector M m. 



Fig. 6. 



Fig. 7. 



The prism p is interposed in this case to render the image of the 

 hand and pencil erect ; a front view of the prism and eye -piece is 

 shown in fig. 6, and a side view in fig. 7. 



In fig. 8, an arrangement is shown by which the object is seen 

 by reflection, and the paper directly. 



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