The news and herald. (Winnsboro, S.C.) 1877-1900, 1879-07-24
sympathetic Inks.

A great number of sympathetic inks
may be obtained by means of reactions
known to Chemistry. For instance,
write on paper with Il colorless solu-
tion of sugar of lead If the water that
is used for the solution be pure, no
trace Of the writing will remain when
it becomes dry. Now hold the paper
over a jet of sulphuratcd hydrogen,
and tho characters will Immediately
appear on the paper of an intense black
color. The following recipes for inks
of this kind arc more simple: If writing
be executed with dilute solution of
sulphate of iron, the invisible charac-
ters will appear Of a beautiful blue, If
the paper be brushed over with PEN
Gil full Of solution OF fyellow prussiate
Of potash; or they will be black. If a
solution of tannin be substituted for
the prussiate. If the characters be
written with solution Of sulphate Of
copper, they will at ooce turn blue on
exposing to the vapors Of ammonia.
Another sympathetic ink Is afforded by
chloride Of gold, which becomes red
dish purple, when acted upon by salt
of tin. A red sympathetic ink may be
made in the following manner: Write
with very dilute solution Of perchlo-
ride Of iron-so dilute, indeed, that the
writing will be invisible wher dry.
BY holding the paper IN tho vapor aris-
Ing from long-necked glass flask con-
tanning sulphuric acid and few drops
of a solution of sulpho-cyanlde Of pot
assium, tho characters will appear Of u
blood red color, which will again dis
appear on submitting them to tho va
pors of caustic ammonia. This expcr-
iment can be repeated nd inflnitum.
During the war in India, some years
ago, important correspondence was
carried on by the English by means Of
the use of rice water as writing fluid.
On the application of iodine, the des-
patches Immediately appeared In blue
characters. sympathetic inks which
are developed under the influence of
heat only, arc much easier to use than
the foregoing. Almost every one, per-
haps, knows that If writing be executed
on paper with clean quill dipped in
onion or turniD juice, it becomes abso-
lutely Invisible when dry; and that
when the paper Is heated the writing
at once makes it's appearance In char
acters Of a brown color. All albumi-
mold, muciiaginous and saccharinc veg
etable juices make excellent sympn-
thetic inks; we may cite, az among the
best, the juices of lemon, orange, apple
and Dear. A dilute solution Of chloride
of copper used for writing Is invisible
until the paper Is heated, when the let
scrs are seen of a beautiful yellow, dis
appearing again when the heat that
developed them is removed. The salts
Of cobalt, as tho acetate, nitrate, sui
phate and chloride, possess like prop
| erty. When dilute solution of these
| salts is used as an ink. the writing, al
though Invisible when dry, becomes
blue when exposed to heat. The ad-
dition Of ohloride Of iron, or Of salt of
| nickle, renders them green, and this
opens the way for very pretty exper-
iment: 1t a winter landscape be drawn
In India ink, and the sky be painted
with q wash Of cobalt alone, and the
branches Of the trees be clothed with
leaves executed with wash Of cobalt
and nickle, and the snow clad earth be
washed over with the same mixture, a
magic transformation at once takes
on the application Of heat, tho winter
landscape changing into summer
scene. ...