Dr. Maddox_, on Photomicrography. 35 
tlie lecture hall_, either as corrected diagrams or^ through the 
additional aid of a properly constructed and well-arranged 
gas lantern, to display these representations to even a widely 
spread audience. This is no narrow question, to be hastily 
set aside, stripped of its legitimate bearings by a prejudiced 
judgment, or the limits of its applicability determined by the 
display of a few dozen objects; rather may they be expected 
to exhibit the failings, weaken the cause^ concede the ques- 
tion, than enforce the truth. Still, wherever difficulty 
attends investigation, science renews her claims, petitions the 
neighbouring branches for support along the widening 
stream of knowledge, and, though she may not at once ac- 
knowledge the debt in full, she passes it to the common well, 
where daily contributaries tend, and leave the issue to a 
future day. Fully persuaded myself that it has advantages 
both of a scientific and art value, and in a belief that it will 
eventually assist the microscopist, it was necessary to test its 
application in the delineation of objects most diverse in 
structure, colour, and size, and with the ordinary full range of 
objectives from the 3-inch to the-yVth; this also without 
any reference to uniformity in the dimensions of the images, 
but bearing in mind the usual loss in definition by too great 
enlargement. The adaptation of the microscope to the 
camera is so generally known that it scarcely seems feasible 
to enter on the arrangement employed, except in a casual 
manner, or to allude to one or two points of practical con- 
venience. I have always preferred a separate instrument 
to the usual microscope, fixed on a stout base board at one 
end, supported by double triangle-legs of convenient height, 
and of a size that it can be handily used in a room at an open 
window. The range of the camera, which has the sliding- 
front removed, is obtained by attaching a bellows portion, 
or a flexible open-ended bag supported at the edges of its 
four sides with stout elastic web, between the camera and 
an upright or square board attached at right angles to the 
base board, near one end, and this piece has a circular 
aperture through which the short and wide body of the micro- 
scope, wheu placed horizontally, slides whilst using the rack- 
and-pinion or the slow motion, which may work near to the 
neck or in the arm of the microscope. To facilitate the use 
of the latter, its milled brass head is deeply grooved and 
turned towards the base board, in which, on its central line 
over the part likely to be traversed by the longest focus 
objective, an oblong slit is cut. Underneath the base board 
is supported a rotating rod carrying a reel on the end beneath 
the slit. A cord is passed round this through the slit and 
