Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1878-12-25

ever, was merely mechanical and the
/ results very crude -si"
"'A great number Of sympath etc inks
may be obtained by means of reactions
known to chemistry. For. instance
write on paper with colorless solution
OF sugar of lead; if the water that is
used tor the solution be pure, no trace
OF the writing will remain when it be-
comes dry. Now hold the paper over a
Jet OF sulphureted hydrogen, and the
characters will imm ediately appear on
the paper, Of an intense black color.
The following recipes for inks of this
KIND are more simple: If writing be
executed with dilute solution of sui
phate Of iron, The invisible characters
will appear Of beautiful blue if the
dry paper be brushed over witha pen
Gil full of a solution Of yellow prussiate
of potash; Or they. will be black, if
solution of tannin be substituted for the
prusslate. If the characters be written
with a solution of sulphate Of copper,
they VIII at once turn blue on exposure
to the vapors Of ammonia. Another
sympathetic ink is afforded by chic
ride OF gold, which becomes a reddish
purple when acted upon by salt of
tin. A red sympathetic ink may be
made IN the following manner: Write
with q very dilute solution of perchlo-
ride, Of iron-so dilute, indeed, that the
writing will be invisible When drv. 3y
holding the paper in the vapor arising
from a long-necked glass flask contain
ing sulphuric acid and few drops of
q solution of sulpho-cyanide of potas-
SUM, the characters will appear of q
blood-red color, which will again disap-
pear on submitting them to the vapors
of caustic ammonia. This experiment
can be repeated ad infinitun1. a..J.r..
during the war in India some wears
ago, important correspondence was car
RED on by the English by means of the
use OF rice water as writing fluid. On
the application of iodine the dispatches
Immediately appeared in blue charac-
tiers. "' f0.' -, IT
i. " Sympathetic inks which are devel-
oped under the influence of heat only
are much easier to use than the forego-
ing. The liquids which possess such a
property are very numerous. Almost
every one, perhaps, knows that if writ
ing be executed on paper with a clean
quill pen dipped in onion or trlrnip
juice, it becomes absolutely invisible
when dry; and that when the paper is
heated the writing at once makes it's
appearance IN characters of a brown
color. All albuminoid, mucilagious
and saccharine vegetable juices make
excellent sympathetic inks; we may
cite, as among the best, the juices of
lemon, orange, apple and pear. A di-
lutte solution of chloride Of copper used
for writing Is invisible until the paper is
heated, when, the letters are seen of a
beautiful yellow, disappearing again
when the heat that developed them is
removed. The salts of cobalt, as the
acetate, nitrate, sulphate and chloride,
possess like properly. When dilute
solution of these salts is used as an
Ink, the writing, although invisible
when dry, becomes blue when exposed
to heat. The addition. of chloride of
IRON, or Of salt Of nickel, renders them
green, and this opens the way for a
very pretty experiment.: If a winter
landscape be drawn in India ink, and
the sky be painted with wash of
COBALT alone, and the branches of the
trees be clothed with leaves executed
with mixture of cobalt and nickel,
and the snow-clad earth be washed over
with the same mixture, mag c trans
formation at once takes place I'm the
application of heat, the winter land
scape changing to a summer scene. r,
g There is a well-kno Wn proprietary
article sold in Paris under the name of
Encre pour les Danes (ink for ladies.
Hager, IN a recent scientific journal,
states that this consists Of an equous
solution Of iodide Of starch, and is
specially intended for love letters In.
four weeks characters written with it
disappear, preventing all abuse of let
tiers, and doing away with all docum en-
tary evidence of any kind in the hands
OF the recipient. The signers of bills of
exchange who use this ink are OF course
freed from all Obligations in the same
length Of time" +'''~.. " -... az