50 PHOTO-MICROGRAPHS. 
IV. ARRANGEMENT OF MICROSCOPE AND 
CAMERA FOR PHOTOGRAPHY. 
Tue simplest arrangement, and that which is 
recommended when the operator is not able to fit 
up an operating-room for the special purpose of 
making photo-micrographs, is to attach the micro- 
scope, placed horizontally, and the camera to a 
piece of board four to eight feet long, in such a 
manner that a line drawn through the axis of the 
tube of the microscope will fall exactly in the 
centre of the ground-glass of the camera. 
It is well to mark the centre of the ground- 
glass with two short lines crossing each other at 
right angles, which may be drawn with a lead- 
pencil or with a diamond. These are to guide the 
operator in centring the field which he proposes 
to photograph. Such a camera as has been recom- 
mended, with the bellows extended, is about two 
feet long; the stand in a horizontal position will 
be fifteen to eighteen inches long. If these are 
mounted on a board four feet long, the microscope 
being placed six inches from one extremity and 
the camera flush with the other extremity, we shall 
have a very convenient and portable apparatus, 
which will do very well to begin with, and which 
may be stretched at any time by simply obtain- 
ing a longer board, placing the microscope and 
camera as before, and introducing a light-proof 
box or cylinder to couple the two parts of the 
apparatus. 
