On a New Camera Lucida. By Br. Hugo Schroder. 815 



whilst the drawing being viewed direct is of course not cut down in 

 field. 



In practice the Microscope should be inclined about 45°, and the 

 image accurately focused through the eye-piece as usual. The 

 camera is then slid on the eye-piece and pushed down more or less 

 until the microscopical image is seen distinctly and the illumination 

 of the field is equal throughout. The drawing-paper is placed on 

 the table immediately under the camera. The observer will then 

 see the microscopical image projected on the paper, at the same 

 time viewing the pencil-point directly. The whole pupil of the eye 

 is available for both images, the diaphragm on the apparatus being 

 considerably larger than the pupil. It may be necessary to balance 

 the illumination either by subduing the light in the Microscope or 

 by increasing it on the drawing-paper. It will generally be found 

 that when the object is in a luminous field the light on the object 

 (especially with lamplight) may be advantageously subdued by 

 ground glass or similar means. The eye may be removed as often 

 as required from the camera and the work recommenced without 

 the slightest shifting of the image ; and with properly balanced 

 illumination, fully shaded drawings can be made with very little 

 practice. The drawing-paper should in every case be placed at the 

 distance of distinct vision, either using spectacles or not. If the 

 vertical position of the Microscope be preferred the drawing-paper 

 may be inclined 45° either in front or at the side of the instrument. 

 For very accurate drawings, in all azimuths, the drawing-paper 

 should of course wholly coincide with the plane of the optical image, 

 as with every other form of camera lucida. A spring clip is pro- 

 vided in which a screen of black paper may be put to shade the eye 

 not in use. 



This form of camera lucida can be modified so as to project the 

 image at any desired angle. It can be used with the dissecting 

 Microscope or hand-magnifier, also on a stand for architectural or 

 mechanical drawings. 



