Monthly Microscopical") 
Journal, Dec. 1, 1869. J 
NOTES AND MEMORANDA. 
329 
the two front corners, to which is hinged at A A (Fig. 1) a second 
frame, also of thin brass, which supports the object or slide-holder. 
Fig. 1. 
Fig. 2. 
These frames are kept asunder at a distance of about y^ths of an inch 
by light springs B B, which can be made so light as to carry as little 
beyond the weight of the stage as is wished — the hinges being so 
constructed as to keep the frames parallel, a result which is also 
effected or supported by the heads of two steady pins at the back of 
the stage. 
The object is carried on the two arms C C, and is held in its place 
by a spring placed over and between them, this form having been 
adopted for greater facility in using the modes of illumination re- 
cently introduced by the President of the Microscopical Society, 
and by Messrs. Powell and Lealand; the former by the use of an 
equilateral prism, and the latter by a pencil of light from a small 
lens of short focus : the whole slides 
on to the present primary stage with 
a dovetail-piece. 
In focussing down on an object 
placed on the safety stage, should the 
worker proceed too far, the upper 
part of the stage yields instantly to 
the pressure, and the object recedes. 
This should in itself be generally 
warning enough, but as it might not 
in all cases be deemed sufficient se- 
curity, Mr. Stephenson has introduced 
a second and very simple instrument 
(Fig. 2) to act as a stop. This con- 
sists of a square rod of brass, marked 
on one face with lines, showing the 
height to which it must be adjusted to 
suit the various object-glasses used: 
it is held in its place by a pin passing 
through it, which is attached to a screw at the outer side of the 
socket in which the rod slides. This little instrument is placed, in 
