280 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



A pantograph for the compound Microscope was described in 1872 

 by Mr. I. Eoberts.* 



Wenham's Mechanical Stage.— This stage is shown in fig. 49, 

 and was first described in connection with Wenham's "Universal 

 Inclining and Rotating Microscope " (now termed " Wenham's Radial 

 Microscope") at pp. 256-7 of the previous volume. 



The stage rotates completely, and is a modification of that of Mr. 

 Tolles, in which the rectangular motions are effected by two milled 

 heads acting on one vertical axis on the surface and entirely within 



Fig. 49. 



the circumference.! It is attached to the limb of the Microscope on 

 the Zentmayer system, that is, by a conical axis that passes through 

 the socket of the swinging tail-piece and through the limb, being 

 secured at the back by a clamp-nut ; it can thus be easily removed, 

 or may be replaced by a glass or other form of stage, &c. The 

 rotating plate is of German silver; a circular rack work is applied 

 beneath, which is turned by a milled-head pinion ; this pinion is fitted 

 so that it can be disconnected from the rackwork by a slight down- 

 ward pressure ; the rotation can then be more rapidly made by hand. 

 The graduations are near the edge of the rotating plate, the index- 

 pointer is therefore in a fixed position, which is convenient for reading 



* Mod. Micr. Journ., viii. (1872) pp. 1-2 (1 pi.). 



t See the descriptions of similar stages, this journal, i. (1881) pp. 116-7 

 (figs. 9 and 10), p. 300 (fig. 46), and for the mechanism of the rectangular move- 

 ments see specially pp. 944-6 (figs. 221-3). 



