change IQUID COLOUR EFFECTS...Water to Ink, Ink to Port, Port to Water

Apparatus.—A decanter of about a pint capacity filled
(as before) with distilled water; seven wine-glasses alike
in shape.
Chemicals.—Tannin, perchloride of iron, oxalic acid.
About as much tannin as will lie on a sixpence is
dissolved in the distilled water in the decanter. Of
the glasses, numbers one and three are unprepared;
numbers two and four contain two drops of perchloride
of iron; number five about ten drops of a saturated
solution of oxalic acid ; number six the same quantity
liquid ammonia; and number seven a small tea-spoonful
of sulphuric acid. On pouring from the decanter, the
first glass (unprepared) gives clear water, the
gives ink, the tliird clear water, the fourth ink once
more (Fig. 1). The* contents of all four glasses are then
returned to the ^ decanter—the whole then appearing
as ink. The first four glasses are then filled from the
decanter, the contents still appearing as ink. A wave of
the magic wand over the fifth glass changes the ink
when poured in from the decanter to clear water, and
a wave in the reverse direction changes the same fluid
to port, or more strictly speaking to claret, in the case
of the sixth glass. The contents of all six glasses are
then emptied back into the decanter, the whole being
claret coloured. Once more six glasses are filled with
claret coloured liquid ; another wave of the wand or
suitable action as the performer fills glass seven
produces clear water once more.
The effect is much heightened if the glasses are not
arranged in a row but apparently haphazard, and
the final and semi-final changes not seemingly made
in any particular glass.
On no account should the contents be tasted.
v This experiment is one of many that can be performed
with quite ordinary chemicals, such as iron (salts),
tannic and gallic acids, salicylates, and such like
chemicals. By dissolving a few drops of ferric chloride
or perchloride of iron in water, the result is a colourless
liquid; but on introducing a few drops of a tannate or
gallate, the liquid is at once darkened, ferric gallate or
tannic galla*te being formed. To restore the liquid to
its original colour a suitable reagent must evidently
be used. Any acid which forms a colourless soluble
salt when added to the tannate would answer the purpose.
Oxalic acid is nearly always used, being the leastCHEMISTRY AND CHEMICAL MAGIC .
corrosive, easy to handle, and portable in a crystalline
form.
If we use a salicylate, such as sodium salicylate, in
place of a tannate, a beautiful purple colour is the
which can be reacted upon or cleared as before.