(99) 
and ocular-glasses is equal to the length of the microscope-tube, 
which originally belonged to the microscope, viz. 15.5 c.M. The 
design of the lenses did not allow to bring the whole slide with 
the ocular nearer to the objective, with a view to increasing the 
illumination. 
Having thus explained the principal features I proceed to a 
detailed description of the apparatus as erected in my laboratory. 
As has been said above, the figures A, G, H of the plate represent 
a side-view of the whole apparatus and a section of some parts of 
it. On the left-hand side of the figure the front part of the projecting- 
microscope, is also shown. The ocular (8) is entirely free from the 
microscope and is mounted on the slide, which rests on a metallic 
cross-beam (10). This cross-beam is fixed before the microscope to 
two projecting rafters of the wall of the small room in which 
the projecting-apparatus is placed. The part of the rope from A 
to G is high up in the lecture-room. ‘The two discs are shown at 
G, and H represents the handle with the ring, which is kept in its 
place by the pin p. 
The slide is shown separately, without the ocular, in fig. B, seen 
from above, and in C a part of it is shown in longitudinal section. 
D is a cross-section of the slide together with the cross-beam (10) 
on which the slide rests and the ring (14), which carries the 
ocular-tube (7). 
Figures KH and F' represent some other parts, which will be 
mentioned further on. 
Proceeding now to a more detailed description of the figures, I 
begin at the left hand side of fig. A, which shows that part of the 
microscope carrying the objective. At 1 we see the head of the 
bar of the projecting-microscope !), «which originally carried the 
whole apparatus. This bar is in my laboratory fixed in a kind of 
fork (2) of which fig. E gives a cross-section. The obliquely de- 
scending metal plates (a) are firmly connected to the wall of the 
room. They carry a bent piece of metal (b) in which the micro- 
scope-bar is fixed by the screw c and the plate d. In fig. A the 
two adjustable pins (e, e) are shown, by which the plate d is kept 
in position. This rigid mounting of the microscope has been found 
1) The projecting-apparatus of the laboratory at Groningen is NewroN’s new 
patent triple rotating electric lantern (N° 5345 of the catalogue), which is furnished 
with the patent electric lantern microscope and micro-polariscope N°, 5350, and a 
Brockre-Perr arc-lamp of 40 Ampères. The lantern is placed on an easily movable 
stand. 
