10 NOTES ON PHOTO-MICROGRAPHY., 
the strips of wood cc, and maintained in position by small 
buttons. There is a hole cut in the top of ZB, corresponding to 
the opening of the camera; this hole, on the under side, is 
surrounded by a circular flange of wood, to which is attached a . 
tube of black velvet about six inches in length. On the bottom 
of B there is a series of wooden blocks, which serve as a support 
for the microscope. The front of the apparatus, shown in Fig. 1, 
has an oblong slit cut in it ; this is bordered on either side by a 
grooved flange, in which a slide works. The slide, e, has a 
circular orifice cut in it, and it can be moved up or down, being 
maintained at any required height by a slight spring ; at the lower 
end it carries a little shelf, on which rests a shallow glass cell full 
of ammoniacal solution of copper sulphate, for the purpose of 
giving a mono-chromatic light. C is the support on which the 
whole rests. It is, of course, necessary that the whole should be 
accurately levelled, and that the base on which the microscope 
stands be parallel with the focussing glass of the camera. 
The apparatus described stands 3 ft. 6 in. in height from the 
floor to the focussing glass of the camera; the wooden body is 
‘r ft. 9 in. long by rod in. wide, inside measure, and 5 in. deep. 
As a source of light, I usually employ an oxy-hydrogen lantern, 
but sunlight or any artificial light may also be employed. With 
the first mentioned illuminating agent the exposure is very short. 
The method of using the apparatus is as follows: * The pre- 
paration is placed on the stage of the microscope, the draw tube 
drawn out, the object roughly focussed, and the instrument placed 
in a vertical position in the centre of the bottom of the body 
of the apparatus, the tube of the microscope, wth the eyepiece 
still in, being inserted in the tube of black velvet and the joint 
made light-tight with an elastic band (Fig. 2 shows the microscope 
in place). The orifice in the slide e is now brought exactly 
opposite to the mirror of the microscope, and the source of light 
* It is unnecessary to refer here to the photographic manipulation of the 
plates ; the introduction of dry plates and the consequent extension of amateur 
photography has resulted in the publication of a number of books on photo- 
graphic manipulation, from which all information can be obtained. 
