A solution of sulphate of iron is to be employed, which
has also been exposed for some time to the atmosphere, and which,
consequently, contains a certain quantity of the red oxide of iron
diffused through it. I should recommend the infusion of galls to be
made of considerably greater strength than is generally directed; and
I believe that an ink, formed in this manner, will not necessarily
require the addition of any mucilaginous substance to render it of
a proper consistence.
I have only further to add, that one of the best substances for diluting
ink, if it be, in the first instance, too thick for use, or afterwards
become so by evaporation, is a strong decoction of coffee, which appears
in no respect to promote the decomposition of the ink, while it improves
its colour, and gives it an additional lustre.
[2] Chairman of the Committee of Chemistry, in the Society for
the encouragement of Arts, Manufactures, and Commerce. This
valuable article is extracted from the 47th Vol. of its
Transactions.
* * * * *
THE SKETCH-BOOK.
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