108 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The base-plate A is 45 cm. long, 40 cm. broad, and 5 cm. deep, so 
that its dimensions are sufficient to adjust conveniently the Microscope, 
the petroleum lamp with the lens, and, if necessary, also the light-filter. 
The base-plate rests on a heavy round oak table, in which is a drawer for 
slides, &c. The under surface of the base-plate is thickly coated with 
felt. 
The wooden pillars B consist of the following four parts : the base a, 
the movable intermediate piece b, and the two rods c and d , of which the 
first is screwed into the base a , while the second d is set on the upper 
end of the first. 
The four-sided bases, which are 14 to 16 cm. high and 6 cm. broad 
and deep, are imbedded in the base-plate, and fixed by screws from 
underneath. Each has a screw-matrix of 3 cm. diameter, in which the 
rod c is screwed. The rotating intermediate piece b has the same 
matrix, and serves to fix the rod c. The rods are 2 cm. thick ; the total 
length of the lower one is 38 cm., that of the upper 31 cm. The upper 
rods d are without screw-threads ; they have at their lower ends the 
Fig. 15. 
Fig. 16. 
blocks e, by means of which they fit over the lower rods ; the rods are 
clamped together by the wooden screw /, which works through a slit 
made in the block. A metal ring g serves to strengthen the block. 
The camera E consists of the following four parts : — the box E, 
12 cm. high, lined with black cloth; the plate frame i of 16 cm. side- 
length and 10 cm. opening for light; the wide camera tube &, and the 
fork C which supports the camera. 
The connection between the upper and lower camera is made by a 
metal catch. The lower camera is attached to the stand in a peculiar 
way (fig. 14, 1', and fig. 15). Beneath the frame on the side of the camera 
is a triangular piece of wood on which a projecting cylindrical socket, 
3 cm. long, is screwed. In this socket fits a fork C, seen in fig. 16 A, 
which consists of a metal bar split down the greater part of its length, 
and having at one end a hole and a pressure screw (fig. 16 B) for fixing 
it on the rod. 
When the lower camera is used alone, it is fastened by the screw l 
on the rod c, and the rod d is removed. The camera can be easily turned 
about the fork C, so as to be inclined in any position. 
