in the ceiling, from three to five feet back of the sitter.
Having arranged this, fasten another string to the side of
the frame, and while the operation is going on in the camera,
swing the back-ground from right to left, continuing this during
the whole time of sitting, and you have a clear "transparent"
back-ground, which throws the image out in bold relief,
and renders the surface of the plate invisible.
If equalled at all it is only by atmospheric back-ground. I
consider it to be the best ever known, and think it needs
but to be tried to afford satisfactory proof that it is so.
Although used by few before, since the first edition of this
work at least two thirds of the operators have adopted its use;
for any one can at once understand the principle and the effect
which it produces."

It may be added that a motion imparted to to any back-ground
where softness is desired, produces an excellent effect.

Gilding Dissolvent.--To one quart of muriatic acid add as much
oxide of iron (common iron rust) as it will dissolve in two days.
This may be done by putting in the oxide in excess.
It should be frequently shook, and when wanted for bottling
it should be allowed to stand in order to settle. When this
is done the solution may be poured off, and reduced by adding
to it an equal quantity of water; then it is ready for use.
This constitutes a gilding dissolvent now in our market.

Solution for Removing Specks.--There is probably no one cause
of complaint so general as "what makes those black specks?"
There are several causes which produce them, and probably the most