282 
Transactions of the Society. 
IX. — Instantaneous Photomicrography. 
By E. B. Stringer, B.A. 
{Bead 20 th April, 1898 .) 
I have now adapted the apparatus described in this Journal, ante , 
p. 174, and figured on p. 175, in the following way. 
To the nose T of the converging system or cone is fitted an 
ordinary drop shutter with pneumatic release. This, at the “ set ” 
position, has an opening, in which is placed a piece of ruby glass. 
Now, when the shutter is “set,” a red non-actinic image is projected 
by the Microscope, which may safely be allowed to fall upon the 
plate. 
The door N at the further end of the camera is opened, and into 
the opening is slid a piece of yellow glass, through which the image 
may be watched, and adjusted and focused upon the plate itself, up 
to the instant of exposure. 
Upon pressing the pneumatic ball the shutter falls, a flash of 
white light passes through the Microscope, and the exposure is made. 
It is better that the^ room should be partly darkened ; the red 
image on the plate can then be seen clearly enough for the most 
accurate focusing. 
In order that the focal point of the red and actinic (or blue) rays 
may coincide, the objective must be apochromatic ; and the plate 
must be an ordinary and not an isochromatic one. But, seeing that 
the living objects which it is necessary to photograph in this way are 
of course unstained, these would in any case be the best conditions. 
It will be seen that the above arrangement can be used without 
in any way permanently altering the apparatus employed for ordinary 
work ; the shutter is, moreover, in such a position that it cannot 
possibly shake either the camera or the Microscope. 
