310 
Transactions of the Society. 
aided by bromide paper enlargements from photomicrographs 
negatives, turned the scales and won a decision in favour of the 
plaintiff. 
Photographs of Photomicrographic Apparatus. 
In the fifth edition (1880) of Dr. Beale’s ‘ How to Work with the 
Microscope,’ p. 309, will be found the woodcut seen in slide 50, 
representing my wet plate apparatus as it stood at that time. The 
old support, consisting of a camera bed about six feet long with a 
single leg at one end and a round table-top expansion with three legs 
at the other, is also the support of my present apparatus. The 
sliding- box camera has been replaced by a bellows camera taking 
plates up to 8 by 10 in. The special Microscope has been replaced 
by a Powell and Lealand No. 3 stand, which with accessories rests 
on the table-top expansion. 
Slides 51 and 52 (figs. 35 and 36) show the general arrangement 
of the apparatus on the table-top expansion. The camera front moves 
freely toward the Microscope, a hole in the front board receiving the 
eye end of the horizontal Microscope-tube until the board comes in 
contact with a black card fitting light-tight about the tube. The 
camera front is easily removed, so the eye can glance through the 
Microscope without changing the position of the instrument, or, so the 
Microscope and all the apparatus for artificial lighting can be turned 
to one side for arrangement and then turned back again. That the 
latter may he done, the Microscope and lighting apparatus stand upon 
a board which revolves about a vertical axis passing through the 
object on the stage. A similar convenience is familiar to you in Mr. 
Pringle’s apparatus.* I prefer, however, to have the Microscope and 
camera constantly connected and to use a secondary horizontal tube, 
at a convenient height for the eye when sitting, projecting at an 
angle of 90° from one side of the ordinary axial tube. A plane mirror 
silvered and polished on its objective surface and set at an angle of 
45° reflects the picture forming rays from the axial into the side tube. 
The eye- piece of the side tube is 10 in. (central measurement 
through the two tubes) from the objective. W hen the position of the 
object and its illumination are satisfactory, the mirror is withdrawn 
wholly into the side tube, allowing the objective to project an image 
into the camera. The axial tube, in addition to having its inner 
surface well blackened, contains a sufficient number of diaphragms to 
thoroughly prevent internal reflection. When an eye-piece is not 
used in the axial tube, a dummy eye-piece, with diaphragms, but 
without lenses, is inserted to prevent reflection from the interior of the 
eye end of the tube, where it is always more or less bright. I have 
found this dummy eye-piece a matter of importance. I believe the 
This Journal, 1800, pp. 513-7, 066. 
