The Sun.
London, England, 1857-12-22 00:00:00

SOCIETY OF ARTS.

At the last meeting of the Society of Arty, Mr. :an
Underwood read a paper "On the history and chemistry
of writing, printing, and copying letters, and a new plan
of taking copies of written and printed documents, marls,
charts, plans, and drawings." Mr. Underwood noticed,
in the first place, the quality of the inks in ancient manu-
scripts, and the attempts that had been made to analyse
their composition, observing that the ink in some manu-
scripts of most ancient date bad retained its colour
much better than that of the manuscripts of the 14th or
15th centuries The opinie,n generally entertained that
all the inks which have longest withstood the test of
rip, are composed of lamp black and a mineraloginous
liquid, has been proved not to be correct; for though
many of them were so formed, it appears, on applying
acid tests, that iron galls were employed as at the pre-
sent day, with the addition, in seme instances, of vas-
pended carbonaceous particles. The difference that
is observable in the preservation of the legibility of
manuscripts was attributed by Mr. -Underwood, in
a great degree, to the different qualities of the parch-
ment on which they are written. With respect, how.
ever, to the manuscripts on papyrus, the ink eroph.syed
on them was formed of powdered carbon, mixed
with *
gummy liquid, and it was most probably used with a fine
brush. In the preparation of ink for modern purposes,
and fitted for the use of steel pens, the plan recommended
and adopted by Mr. Underwood is—first to bruise the
galls very small, but not into powder, and to steep them
for several days in distilled water, the purity of the water
being considered important. To that infusion there. is
added a quantity of iron in filings or coiled wire, which
after a short time turns the liquid black—iron being
preferred to copperas (sulphate of iron), which is com-
monly used, biicame the sulphuric acid of the sulphate
becomes disengaged from its combination with the-
and tends to turn the ink brown. Logwood and
gum are subsequently added to give a blue colour.
and adhesiveness to the ink. The new plan of copy-
ing writing consists principally in preparing the
paper, by steeping it in a weak solution of
chromate of potass, which facilitates the .transfer of the
ink ; and wit
it, h a paper so prepared, and a
been taken of
the original writing, by allowing the paper to remain a
short time in the ordinary copying press. Specimens of
writing so transferred were exhibited, of some of which
25 copies had been taken. In the discussion that ensued
lir. Lloyd, after alluding to the importance, to the legal
profession particularly, of obtaining copies that would
retain their legibility, suggested the application of pho-
tography to the purpose, and mentioned several instances
in which it had been so applied successfully. Mr. May
observed that the chlorine now used in bleaching writing
paper had the effect of destroying all vegetable colouring
matter in the ink, and he conceived that no ink would be
durable that depended on a vegetable colour. ?Ir. Ste-
phens advocated the use of blue ink, made with Prussian
blue, as more durable than black ink, and he ridiculed the
objection to the use of blue ink in legal documents which
had been raised by the judges. Mr. Atwell, the
inventor of anastatio printing, contended that when a
large number of copies was wanted, especially of maPss
his process is more applicable than the common plan of
copying from paper, as the original, when transferred
to a metal surface, can be multiplied to a greater extent
and with more perfect resemblance to the originaL
After some observations from Mr. Underwood, explain-
ing the peculiar fitness of his plan of copying for railway
purposes, the meeting adjourned.