previously, the varnish flows more freely and leaves a thinner coating
of balsam behind on the transparency. When the plate has ceased to drip,
place it in a plate drainer, with the corner you poured from lowest, and
leave it where dust cannot get at it for four or five days, when it will
be found sufficiently hard to be put into a plate box. The transparency
may be finished at any time afterward by putting a clean glass of the
same size along with it, placing one of the blank paper masks sold
for the purpose--either circular or cushion-shaped to suit the
subject--between the plates, and pasting narrow strips of thin black
paper over the edges to bind them together. This method is very
successful, as you may see from the examples. It renders the high lights
perfectly clear, and leaves a film like glass over all the parts of the
transparency where the varnish has flowed.

In order to avoid the risk of dust involved in this process, I tried
other means of arriving at similar results and with success, for the
plates I now submit to you have been simply rubbed or polished, as I
may say, with a mixture of one part of Canada balsam to three parts of
turpentine, using either a small tuft of French wadding or a small piece
of soft rag for the purpose, continuing the rubbing until the plate is
polished nearly dry. This method is particularly successful, rendering
the clear parts of the sky like bare glass. I have here a plate which is
heavily veiled--almost fogged, in fact--one half of which I have treated
in this way, showing that the half so treated is beautifully clear,
while the other half is so veiled as to be apparently useless.

I have tried to still further simplify this necessary clearing of those
plates, and find that soaking tor twelve hours in a saturated solution
of alum, after washing the hypo out of the plate, is successful in a
large number of cases; and where it is successful there is no further