WRITING INK. 
s 
East Indian 
and otlier 
inks. 
run or spread.. The most concentrated sulphuric acid, or oil of 
vitriol, being dropped upon the writing, and suffered to remain 
several days, was found to have nearly destroyed the paper, but 
not the writing. And I cannot conceive any purpose, depending 
upon the fixity, durability, and indestructibility of ink, which 
may not be answered by this composition, there being, as I am 
persuaded, no chemical agent, nor any length of time, which 
can efface its impressions, without destroying the paper or parch- 
ment on which they are made. 
In some parts of the East Indies, a permanent writirfg ink 
is formed, by dissolving the brownish black liquid contained in 
the oriental marking nms, (seraecarpusanacardinm,) mentioned 
at p. 308 of my first volume. The solution is to be made by 
an alkaline lixivium, and afterwards neutralized by vinegar. 
There are some few instances of inks said to be producrd by 
vegetable colouring matters upon the basis of alumine instead 
of iron : one of these, first mentioned by Ray, and aherwards 
by Linnaeus,* is from the poisonous berries of the aclea spicata, 
or common black-berried herb Christopher. Linnaeus also 
mentions the fruit of the impetrum procumbens, as affording 
another such ink. I believe, however, that neither of these 
can be lasting, 
Barham, in his Hortus Americanus, mentions the pods of 
the mimosa juliflora, improperly called poponax in Jamaica) 
as affoiding a good ink on a similar basis,- He says, “they 
soak some of the pods all night in water, then mix a little alum 
with it, and boil it to a due thickness, which makes a very fine 
black and strong ink 5 ” and he adds, that he had often made and 
written with it. Reflecting, however, upon the family and genus 
to which this tree belongs, I am persuaded, ihatthe black which 
it affords must be produced by iron, which might very easily 
be dissolved, partly by the astringent vegetable matter, and 
partly by the acid part of the alum contained in the infusion, 
while the latter underwent the boiling which is prescribed, if 
performed, as it doubtless must have been, in an iron vessel j 
and this, probably, is the fact, also, in regard to the natural ink, 
which toe inspissated juice of the old trees of the fagus castanea, 
Lin. 
