595 
XII . — Photomicrographic Camera , designed chiefly to facilitate the 
Study of Opaque Objects, more especially in the Study of 
Palseo-Botany. 
By J. Butter worth, F.R.M.S. 
(Bead 21 st October, 1896.) 
Plates XIV. and XV. 
In drawing the attention of the Society to this camera, I do not do 
so with any idea that any of its parts may be in any way original. 
My wish is to draw attention to its application to both opaque and 
transparent objects in photomicrography. It was, however, with a 
view to adapting the camera to photographing opaque objects that 
first led me to experiment in photomicrography, and I have long seen 
that a wide field is open to photography in this direction ; in illustra- 
tion of this I may instance my own study of ‘ The Fossilised Plants 
of the Lancashire and Yorkshire Coalfields.’ Having been engaged 
in this study for nearly thirty-five years, most of which time I have 
been a colleague of the late Prof. W. C. Williamson, and as such I 
have seen not a little of the difficulty of sketching by hand the struc- 
ture of these coal plants with a view to their description, and yet I 
can vouch for the great accuracy of the above gentleman’s drawings, 
knowing as I did hi3 method of procedure, which was by aid of the 
camera lucida, micrometer, and paper ruled to scale. 
Up to the advent of isochromatic photographic dry plates and the 
use of colour screens it had always been a very great difficulty to get 
a good photograph from sections of coal plants, owing to the amber 
colour of the section, and, though the difficulty of the colour is to 
some extent removed by the use of the above plates, still the section 
has to be ground so thin to give it sufficient transparency that many 
EXPLANATION OF PLATES. 
Plate XIV. 
A is the base-board of camera. B, bellows of usual form and size. C is the 
foundation-plate, screwed to camera-front, carrying the lens-tube, horizontal bar, 
rack, &c. D is the carriage, carrying lamp E, object-stage F, concave reflector G, 
and small bull’s-eye reflector H. I is the main lens-tube carrying adapters or other 
tubes to suit battery of lenses. J is a bracket carrying a double-forked lever K for 
fine focusing, which is actuated by the threaded pulley working on the long screw 
L, while said pulley is revolved by the small side-shaft M through the belt N. O is 
a support for the outer end of the horizontal bar. The dotted lines show the path 
the light takes on its way from the bull’s-eye condenser of lamp to the object. 
Plate XV. 
Transverse section of Astromyelon cut at the fork where the plant was branching ; 
also a transverse section of Cardiocarpon is shown lying near ; from the lower co'al 
measures near Oldham, x about 15 diameters. Photographed opaque. 
