[Footnote 2: Since this paper was read, I have seen in the
office of the City Engineer of Boston a drying case which is
similar in some respects to the one that I have devised. It has
been longer in use than my own. The drawers are simply the
ordinary mosquito netting frames covered with cotton netting.
They have no fronts, but a door covers the front of the case,
and shuts out the light.]

_The Portfolio for Protecting the Sensitized Paper from Exposure to
Light._--The sensitized paper is very well protected from exposure to
light, if kept in a portfolio or book, the brown paper leaves of which
are considerably larger than the sensitized sheets. The sheets may be
returned to such a book after exposure, and washed at the convenience of
the operator. They can be washed more quickly and perfectly if _two_
water-tanks are provided in which to wash them. A few minutes' soaking
will remove nearly all of the sensitizing preparation which has not been
fixed by the exposure. If the soaking is too long continued in water
that is much discolored by the sensitizing preparation, the sheets
become saturated with the diluted preparation, and they may become
slightly colored by _after_ exposure. If the first soaking is not too
long continued, and if the sheets are transferred at once to a second
bath of clean water, which is kept slowly changing from an open faucet,
they may remain there until the soluble chemicals have been entirely
extracted, and there will be no risk of staining by after exposure.
Washing in two tanks is of more consequence when the ground is white and
the lines blue, than when the ground is blue and the lines white.

_The Grades of Paper that are well Adapted for Blue Process Work._--I
have tested many grades of paper, to ascertain if they were well adapted