be wise to weigh this point carefully, and act upon it, before the
enlightened public have raised a cry against the pernicious practice
and made photographers smart for their want of applying timely remedial
measures to a decided evil.

On reading the above again, fearing lest any misconception should arise
in the mind of the reader, I deem it expedient, to clearly state that
for terra-cotta recourse is had to double transfer; that is, the picture
first taken is lifted from the support on tracing paper, put in
the right position on terra-cotta, and pressed down while wet with
blotting-paper, left to dry, and is then so far ready.

Respecting the production of pictures by means of emulsion, ground opal
being the best, the system I employ is as follows: After well cleaning
the glass, coat it with emulsion (which had better not be too thick).
When dry it is exposed and developed with the usual oxalate developer,
to which a little bromide of potassium has been added. The remainder of
the operations is as usual. Those varnished with dead varnish can be
tinted and worked up with colored crayons or black lead pencil and make
very pleasing pictures. It is needless to add that they are also to be
finished in water-colors if thought preferable.--_G. W. Martyn, in Br.
Jour. Photo_.

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PAPER NEGATIVES.