ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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and can be raised or lowered so as to transmit the light through the 
lenses of the objective B. A prism K is interposed in order to render 
the pencil of light parallel to the axis of the Microscope before it enters 
the objective. 
The mirror C and the prism K are pierced to allow of the passage of 
n conical tube J, through which the image of the preparation H formed 
by the objective is observed. 
Fig. 17. 
M. Marey, in reference to this new apparatus, considers that it might 
find useful application in the reproduction by chromophotography of the 
movements of microscopic creatures. With the ordinary illumination 
the objects detach themselves on a luminous field, and the successive 
photographs are taken on a movable plate. It would be preferable, with 
a dark field, to photograph successive images of the object on the same 
immovable plate ; and the possibility of doing this for microscopic 
objects might be realised with M. Fremont’s instrument. 
C3) Illuminating and other Apparatus. 
Zeiss’ Vertical Illuminator.* — This serves to illuminate opaque 
objects from above. As seen in fig. 17, it is inserted in the form of an 
* Zeiss’ Catalogue, No. 30, 1895, p. 65. 
