ZOOLDGY AND BOTANY, MICROSCOPY, ETC. 



699 



of a thumb- screw passing through a hole in the centre of the disk. 

 The specimens are carefully mounted, so that their centres are at an 

 equal distance from the centre of the disk, and are covered with £-in. 

 slips. In this way each disk will carry twenty specimens. On the 

 shaft carrying the hard rubber button by which the small pinion is 

 turned is an intermittent sear arrangement which drives a dial with 

 figures or names on it, indicating the specimens as they come under the 

 objective. The whole instrument (fig. 102), with the exception of the 

 ocular and the hard rubber button, is inclosed in a glass case, the 

 focussing being accomplished by raising or lowering the ocular ; a set- 

 screw preventing its being removed from the draw-tube. 



Societe Genevoise Second Large Model Microscope.* — This in- 

 strument (fig. 103) is of similar but lighter construction to the Micro- 

 scope previously described and figured in this Journal. | 



Fig. 103. 



- Culmann's Monocular Image-Erecting Prism-Microscope.J — This 

 instrument (fig. 104), constructed by the Zeiss firm, has been designed 



* k Cat. Soc. Genevoise pour la Construction d'Instr. de physique et de me'canique, 

 1900, p. 99. f See this Journal, 1884, pp. 281-2, figs. 30 and 31. 



X Zeitschr. wiss. Mikr., xx. (June 1904) pp. 416-20 (1 fig.). 



