P.S.--In a day or two I shall send you a _recipe_ for easily turning to
immediate use the "used-up dipping baths" of _nitrate_, without the
troublesome process recommended to one of your correspondents.
_Ferricyanide of Potassium._--I have used with success the ferricyanide of
potassium (the _red_ prussiate of potash, as it is called) for removing the
stains contracted in photographing. This it does very readily when the
stains are recent, and it has no injurious effect upon cuts and sore places
should any exist on the hands. An old stain may with a little pumice be
very readily removed. I have mentioned this to several friends, and, if not
a novelty, it is certainly not generally known.