ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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The upper camera F consists of two wooden frames m and w, with a 
bellows between which can be drawn out to 20 cm. The upper frame is 
solid and is provided with two grooves and a catch which closes 
automatically after the slide has been introduced, and can be easily 
opened by pressure of the finger when the slide is to be taken out. 
The upper part of the camera and its connection with the uprights is 
more complicated. By this connection the camera stands vertical, is 
movable on the rod d , and can be fixed in any position by the screw Z'. 
The blocks D which fit over the uprights carry forks o, o', which sup- 
port the corners of the frame. 
Fig. 17. 
Of the slides shown in fig. 17, A is for the lower camera, B for the 
upper. 
The small slide consists of the frame a, with the cover b, and the 
slider c. The larger slide B is similar. Its size is 16 X 18 cm., but 
it can be used for plates 8 x 8, 8 X 10, &c., by inserting frames like 
that shown in C. 
The First Photomicrogram in Natural Colours.* — Dr. R. Neuhauss 
has made experiments in photography in natural colours by the methods 
of Valenta*]* and met with considerable success in the reproduction of 
mixed colours. An experiment was made in taking in natural colours a 
photomicrogram of a preparation of Distomum lanceolatum coloured 
bright red, with the internal organs black, yellowish brown, and dark red. 
The picture was taken with a linear magnification of 9 times, and with 
the use of the Auer incandescent light and Hartnack projection system 
on a bromsilver plate prepared by the method of Yalenta. The plate 
w T as about ten thousand times less sensitive than those generally used for 
* Zeitschr. f. wiss. Mikr., xi. (1894) pp. 329-31. 
f Yalenta, E., ‘ Die Photographic in natiirlichen Farben,’ Halle a. S., 1894. 
