magnificent gold-green crystal crown, like nothing
in nature ever yet beheld, challenges public
admiration as "acetate of rosaniline." And now
I am coming upon dangerous ground. The
metals were all very well, and even I, a
confessed ignoramus, could make out something
about them; but now when we are diving deeper
into the chemical labyrinth, I must hold my end
of the clue very firm, not to get utterly lost and
bewildered. Well, this gold-green crown is
called rosaniline; and rosaniline is aniline that
turns a bright rose-red in alcohol; and aniline
is got from the "basic oil of coal-tar," whatever
that may be, and also in any quantity from
indigo.  This gold-green crown is very curious
and very lovely. It is worth about four hundred
pounds (at first the report went that it was
worth a thousand), and one grain of it would dye
a bucketful of water, deep magenta: and the
whole crown itself would dye the Thames
magenta from the sea to its source. Aniline is the
material whence have been got the last two
fashionable colours, mauve and magenta. A
little way off, is a large bronze-coloured cylinder,
called "solid purple aniline," worth eight
hundred pounds, and capable of dyeing a nation's
wardrobe the best shade of mauve. Mauve was
originally sold at its weight in gold, for all that
it was made of dirty bad-smelling coal-tar; but
the secret has been found out now, and mauve
and magenta fetch no more than some other dyes,
though in the end a little dearer, because more
fugitive than many others. In this case there
are glass cups holding various coloured anilines:
green, and blue, and yellow, and dull red, and
purple, and dirty-looking mauve, all products of
this basic oil of coal-tar under different conditions;
as "precipitated," and "oxalate," and
"sulphate," and "chloride," and "arseniate,"
and "crystallised;" only I cannot fit the name
and condition together. Then there is some
"magenta powder," a beautiful mass of rainbow-
coloured grains, like crushed peacock ore; and
a curious blue fluid called arneline, which the
label tells us is also got out of aniline; and
there are aniline orange, and aniline deep purple,
and cyanine blue from aniline, and opaline blue
from aniline; and all these last are liquids, and
very bright and clear. There is another very
brilliant colour got from coal-tar, called rosolic
acid, which, if any one could fix as a dye, would
make his fortune. But as yet rosolic acid is
fugitive and shy, and fades away after a few
hours' exposure to the light. But it is such a
crimson! A blood-red damask rose would look
pale beside it.

Then there are two crystal columns, which
make part of Cinderella's story quite possible.
One is a magnificent collection of eight-sided
gorgeous yellow crystals; the other of blood red;
the first is called the yellow prussiate of potash,
the second the red prussiate of potash, and is
made from the yellow. Very grand and glorious
the colours of both! A maiden adorned with
gems of these prussiates would outshine an
Eastern queen for magnificence of jewellery; but
fling a cup of water over her, O spiteful eldest
sister, or malignant fairy uninvited at her birth,
and the guards would see nothing but a poor
little beggar-girl, with never a ruby or an
amethyst upon her. For, water dissolves our
prussiate of potash gems as quickly as it would
dissolve a few grains of salt or sugar. These
prussiates are got out of hoofs of cattle, blood,
waste bits of skin, horns, hides, old woollen
rags, and even dried fungus. The yellow
prussiate makes the well-known "Prussian blue"
when mixed with iron salt; though I confess,
privately, I do not know what iron salt is
exactly. Potash does a great deal in the world.
There is, first of all, oxalate of potash, better
known as salts of lemon, that is, a mixture of
potash and oxalic acid; and there is pearlash,
that is roasted potash, with all the carbon and
sulphur roasted out of it; and there is caustic
potash, which seems to be something like the
universal solvent, and can dissolve almost anything,
whether flint or silk, sulphur or wool. It should
never be touched with the tongue or fingers,
unless you are desirous of a burn and a blister.
Then there is carbonate of potash, or salts of
tartar, which helps to make effervescing drinks,
and citrate of potash, which is merely citric acid
and that same potash carbonate, in its fizzing
state called effervescing lemonade and kali; and
nitrate of potash, otherwise called nitre and
saltpetre, good for corning rounds of beef and
making gunpowder; and bitartrate of potash,
which is cream of tartar, good for cooling heated
blood, and got from the fermenting process of
wines — called red or white argol, according to
the colour of the wine fermenting. And potash
generally is the "salts" of vegetables, the
largest proportion of which exists in the fumitory,
and the smallest in the wood of the pine.
Its metallic base is the metal called potassium,
and the iodide of potassium, which is a certain
preparation of iodine and carbonate of potash, is
one of the prime agents in the photographer's
studio, and, if I mistake not, is also often to be
seen in certain scrawling hieroglyphics on medical
prescriptions.

Go a little further and you will see a mass of
white grains and crystals, called oxalic acid,
originally got out of the sorrel plants, but,
because there is not enough sorrel in the world,
now made from sawdust, heated with a mixture
of caustic soda and potash. John Dale, of
Manchester, makes seven tons a week of oxalic
acid, and sells it for ninepence the pound,
though formerly it was ruinously dear — to the
great saving of calico printers, who use it as a
discharging, not colouring or fixing, agent.
Oxalic acid whitens linen and top-boots, takes
out fruit-stains, and is obtained from starch,
gum, sugar, and treacle, as well as from heated
sawdust. Near at hand is a grand lump of
white-streaked blue-green copperas, of marvellous
beauty, if of common uses, for it is only a
"salt" made by copper and sulphur in certain
combinations, and called blue vitriol and blue
stone by the world at the laboratory door. But
then, indeed, the emerald or royal malachite is
only flint and carbonate of lime coloured with