236 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
MICROSCOPY. 
o. Instruments, Accessories, &c.* 
(1.) Stands. 
New Student’s Microscope. — Mr. E. M. Nelson made tbe following 
remarks when exhibiting one of Messrs. Watson’s Edinburgh Student’s 
Microscopes with a tripod foot, having an equilateral base whose side 
is 6J in. : — “Without dwelling on the ordinary movements, which have 
been described before, merely mentioning that they are sprung through- 
out, I will pass on to what may be called the novelties. The first is in 
the rotating nose-piece. This I have had considerably lightened by 
doing away with the loose adapting screw, and making it a part of the 
fixed nose-piece of the Microscope. It will be seen that it now forms a 
part of the body, which can only be removed by taking out the three 
screws which usually fasten the ordinary nose-piece on the body. A 
rotating nose-piece is not one of those pieces of apparatus you sometimes 
use and at other times dispense with, therefore there can be no objection 
to fixing it permanently to the Microscope. 
The second novelty is in truth an old friend. It is what on a former 
occasion I called a semi-mechanical stage ; in other words, it is a stage 
with a mechanical movement only in a vertical direction (fig. 15). 
This you will find an important movement in an advanced student’s 
Microscope. But before proceeding allow me to again state that what- 
ever appliance you may put to a student’s Microscope it must leave the 
stage perfectly plain. Our Continental neighbours sometimes spoil a 
stage by screwing pieces of watch-spring to it. 
This stage is to all appearances one of my plain horse-shoe stages, 
fitted with a sliding bar, which can be entirely removed. On closer 
inspection you will see that the edges of the stage are connected with 
the mechanical movement underneath the stage (tig. 17). 
These edges have 3/4 in. of movement by spiral rackwork, the 
movement being sprung, and the pinion which is carried through has a 
head on either side of the stage. 
The sliding bar slides on these mechanically moving edges, and, con- 
sequently, it can be moved either by the rackwork or by the hand. 
There is an important point which was omitted in my first drawing of 
this movement; this I soon rectified by making the ledges bear down- 
wards, instead of upwards ; if this were not done, a manipulator who 
rested his hand against the edge of the stage would bend down the 
guiding lugs, and so injure the whole movement ; but by making the 
ledges bear downwards no injury can happen by pressure from above 
(fig. 16). 
A semi-mechanical stage will be found a great convenience. Every 
one who has worked with the Microscope knows what an immense 
advantage a sliding bar is. It holds your slip and enables you to run 
* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- 
minating and other Apparatus; (4) PLotomicrugraphy ; (o) Microscopical Optics 
and Manipulation ; (6) Miscellaneous. 
