116 



SUMMARY OF OUKRENT RESEARCHES RELATING TO 



natural size. The arms can be raised and lowered by the sliding 

 within A of the support to which they are attached, the screw on the 

 right clamping it. 



Fig. 12. 



Jung's New Drawing Apparatus (Embryograph) for Low 

 Powers.* — H. Jung was induced, by the inconvenient or ineffective 

 performance of other drawing apparatus, to construct a new one 

 (fig. 13) in accordance with the friendly advice of Professor v. Koch, 

 giving powers of about 1 to 20 or 4 to 30 in continuous succession. 



Upon the heavy square iron foot rests (besides the column and the 

 bar P, movable by rack and pinion) a concave mirror to illuminate 

 transparent objects. The latter is 80 mm. in diameter, and consists 

 of a plano-convex lens silvered at the back. It is supported on a 

 hinge-joint, which is attached to a short rod fitting into a spring- 

 tube Ji, and this is screwed to a carrier T having a longitudinal slot. 

 The carrier rests on the foot to insure greater stability, and on 

 loosening the screw S which clamps it, it can be moved so as to obtain 

 any desired position of the mirror, either by turning it round the 

 screw as a pivot, or by sliding it along the slot. 



Upon the column is a stage 75 mm. deep, and 108 mm. wide. 

 The stage, instead of a round aperture in the centre has a horseshoe 



* Zeitschr. f. Instrumentenk., iii. (1883) pp. 165-7 (2 figs.). 



