. The microscope; an introduction to microscopic methods and to histology. Microscopes; 1899. CH. V.] DRA WING WITH THE MICROSCOPE. 115 known angle in a moment, then the drawing board can be hinged and the elevation of 10° and 20° determined with a protractor. The draw- ing board is very conveniently held up by a broad wedge. By marking the position of the wedge for io° and 200 the protractor need be used but once, then the wedge may be put into position at any time for the proper elevation. § 175. Abbe Camera and Inclined Microscope.—It is very fatigu- ing to draw continuously with a vertical
. The microscope; an introduction to microscopic methods and to histology. Microscopes; 1899. CH. V.] DRA WING WITH THE MICROSCOPE. 115 known angle in a moment, then the drawing board can be hinged and the elevation of 10° and 20° determined with a protractor. The draw- ing board is very conveniently held up by a broad wedge. By marking the position of the wedge for io° and 200 the protractor need be used but once, then the wedge may be put into position at any time for the proper elevation. § 175. Abbe Camera and Inclined Microscope.—It is very fatigu- ing to draw continuously with a vertical microscope, and many mounted objects admit of an inclination of the microscope, when one can sit and work in a more comfortable position. The Abbe camera is as perfectly adapted to use with an inclined as with a vertical micro- scope. All that is requisite is to be sure that the fundamental law is observed regarding the axial ray of the image and the drawing surface, viz., that they should be at right angles. This is very easily accom- plished as follows : The drawing board is raised toward the microscope twice as many degrees as the mirror is depressed below 45° (§ 174), then it is raised exactly as many degrees as the microscope is inclined, and in the same direction, that is, so the end of the drawing board, shall be in a plane parallel with the stage of the microscope. The mirror must have its edges in planes parallel with the edges of the drawing board also (Fig. no). Fig. 110. Arrangement of the drawing board for using the mi- croscope in an inclined position with the Abbe camera lucida {de- signed by Mrs. S. P. Gage).. A very elaborate and convenient drawing board has been devised by Bernhard (Zeit. wiss. Mikroskopie, Vol. XI, (1894) p. 298), whereby the proper inclination can be given the drawing board for the vertical microscope and also for an inclined microscope. The drawing surface as a whole can be raised or lowered to meet the needs of different ob- jects
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