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Rubric Lakes Or Field's Lakes Are Derived From The Root Of Rubia

tinctorum," a plant largely grown in France and Holland, whence the bulk
of that used in England is obtained. The French madders are in a state
of very fine powder, containing one half their weight of gum, sugar,
salts, and other soluble substances, which water speedily dissolves.
Madder roots in the unground state are imported from the Levant, and
called Turkey roots. Good qualities of Turkey madder yield near sixty
per cent of extractive matters, a term that includes everything
removable by water and dilute alkalis: the woody fibre is therefore
about forty per cent. This is presuming the root to be genuine, for
madder is often adulterated with brickdust, red ochre, red sand, clay,
mahogany sawdust, logwood, sandal and japan-wood, and bran.

Unlike cochineal, madder possesses several colouring matters; the
question of which, despite the learned researches of Dr. Schunck and
others, is far from settled yet. The following remarks embody our own
experience of the root, simply as a pigment-producing product:--

Madder contains five colouring matters--yellow, red, orange, purple, and
brown. Of these, the first colour is soluble in cold water. By washing
the powdered root quickly with it by decantation, the yellow and brown
are extracted in the form of an opaque liquid. If this be decanted and
allowed to stand, the brown deposits, leaving a clear buffish-yellow
supernatant liquor. In the root from which the extract was poured, the
remaining three colours are left. On adding a strong boiling solution of
alum, these are dissolved, yielding a fine red liquid. From this there
can be thrown down, by the agency of different chemicals, a red, an
orange, or a purple precipitate. Or, supposing the whole of the
colouring matter to be deposited as a red lake, it is possible to
convert this--also by the agency of different chemicals--either into
orange or purple. Hence, for all practical purposes, madder contains but
three colouring matters: a yellow, soluble in cold water; a brown, not
soluble in, but capable of being extracted by cold water; and a red,
soluble in boiling alum, and furnishing at will a purple or an orange.

As was observed in the previous chapter, no good pigment is obtained
from the yellow, of which the less there is present the better; but the
brown affords a valued product, which will be duly noticed. It is
essential to the purity of the reds, that the madder should be freed
from both these colours; and it was probably due to insufficient aqueous
washing of the root, that the old lakes were dull and muddy, mere
brick-reds of ochrous hues. For many years, however, lakes have been
prepared perfectly transparent, and literally as beautiful and pure in
colour as the rose; qualities in which they are unrivalled by the lakes
and carmine of cochineal. They have justly been considered as supplying
a desideratum, and as among the most valuable acquisitions of the
palette in modern times, since permanent transparent red and rose
pigments were previously unknown. The red varieties range from rich

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