206 BOTANICAL GAZETTE [SEPTEMBER 
focal length be used, sufficient bellows must be at hand to permit the 
ground glass to be fixed at 15 inches from the objective. The modem 
“long-focus”’ cameras provide very fully for this need and others which 
will appear upon trial. The best work will be possible if a lens is 
chosen of rather short focal length, one technically known as a “wide- 
angle” lens. Not only is the 
range of the camera thus in- 
creased, but the sharp focus 
over a considerable depth 
which is absolutely requisite 
in morphological work is far 
more easily obtained. 
In focusing, it will be 
found a decided advantage 
to select a spot in the object 
or composition upon the glass 
shelf a little above its vertical 
center, and there to affix tem 
porarily a white card or paper 
with fine lines. An ordinaty 
visiting card 1 
When this is focused "po 
and the lens then « stopped 
down,” the whole object 
will be sufficiently shatp. 
We urge extreme and 
cleanliness in 4 
graphic operation 
care 
ll photo 
enemy ; every grain is willing to be photographed. 
A skylight is most undesirable for vertical photography, P&€ 
the reflections upon the glass platform. Indeed, the worker will 
: . Imost essential to guard against reflections from the 
ceiling of a light room, and particularly from the poli 
front and lens, by preparing a wire frame or hood, covere 
Nec or the like, and extending about the camera SO 4S to cu 
tmmediate top light—F. A. WaucH and J. Horace 
because of 
find 
shed camer 
5. In work: | 
ing full size, dust 1s 4 oe : 
skylight, 
d with black zo 
t off a . 4 
