UUl 2 1897 
JOURNAL 
OF TI1E 
ROYAL MICROSCOPICAL SOCIETY. 
JUNE 1897. 
TRANSACTIONS OF THE SOCIETY. 
Y . — On a New Mechanical Stage. 
By Edward M. Nelson, President R.M.S. 
{Bead 2Ut April, 1897.) 
I have the honour to bring before the Society an improved mecha- 
nical stage which Messrs. Watson and Sons have made from my 
drawings. 
The improvement consists in converting my semi-mechanical 
horse-shoe stage, figs. 11, 12, and 13 (exhibited here in February 
1893 *) into a completely mechanical movement.! 
This has been carried out in the following manner. The sliding 
bar has been slotted, fig. 14, and a movable piece, which may be 
called the shuttle, has been fitted in the slot ; this shuttle has 
diagonal rack-work at the back, and a vertical spiral pinion gears in 
it, fig. 15. Above this pinion there is a horizontal bevel-wheel, 
which is geared by friction to a vertical wheel fixed on the usual 
horizontal pinion. The cock which holds, and is close to, the ver- 
tical bevel wheel in fig. 15 is slotted underneath; a capstan-headed 
screw (not shown in the figure) is fitted for the purpose of compress- 
ing this spring part ; the amount of friction between the copper bevel 
wheels can therefore be regulated at will. This capstan-headed screw 
is placed some distance from the bearing, so that the length of the bar 
between it and the bearing may form a stiff spring ; this renders the 
motion equable. It will be noticed, therefore, that the transverse 
movement is confined to the sliding bar. This sliding bar can be 
removed so as to leave the stage perfectly plain. The heads of the 
pinions which control the vertical movement have been kept below the 
level of the stage, so as to be out of the way of culture-plates (fig. 12). 
In deference to the views expressed by Mr. Michael in his last 
* Journ. R.M.S., 1893, p. 236. 
f The 1893 stage was itself an improvement on a previous model I had designed 
and exhibited in 1888. All the main ideas in the plan of the 1888 stage are em- 
bodied in this new one, the alterations and improvements being in the mechanical 
details. See Journ. E.M.S., 1888, p. 477. 
1897 
0 
