distance apart. It is better to place between them a thin sheet of finely
ground glass, as this overcomes the bad effects of slight flaws in the
lenses, which are not uncommon. The combination is then boxed up.

[Illustration: Fig. 8]

Having now our light-box, condensers, negative box, camera and screen,
they are next arranged in the order shown by Fig. 9. A long table
especially constructed for the purpose makes the best base for this
purpose.

In putting the apparatus together there are several points to be noticed.
First, the planes of the lenses, negative, projecting lenses and screen
must all be parallel; second, the centers of all these should be in a
single straight line, and third, either the light or the condensers should
be so mounted as to easily slide backward or forward, since every time the
projecting lens is racked backward or forward it necessitates a
corresponding motion of the condensers to or from the light.

[Illustration: Fig. 9]

In constructing the apparatus, for use with condensers and artificial
light, the same provision should be made in the negative box for inserting
a piece of colored or ground glass as was made in the daylight apparatus.
When the diameter of the condensers is but little greater than the
diagonal of the negative it will be necessary to have the latter quite
close to the former, as the cone of light from the condensers has its apex
at the lens, and hence if the negative in such a case is at a distance
from the condensers the corners will receive no light. Reference to Fig. 9
will show this plainly. For this and other reasons it is always best to
have the condensers of ample size for a given negative. In fact, before
beginning to make enlargements the worker should work with one good
negative until he finds out exactly what light-intensity is best suited to
it. This will then serve as a standard for all other negatives of the same
general grade, and variations of the light can be made as required for
particular negatives, or where the extent of enlargement is materially
changed for various purposes.

In using the daylight apparatus, which we will now consider, the negative
is placed in the holder opposite the center of the ground-glass, upside
down and facing into the work room. The room is darkened and lens
uncapped. An image more or less blurred will appear on the screen. If the
enlarged picture is to be only slightly larger than the negative, the lens
must be racked