Sandal Red
:
ON THE PRIMARY, RED.
We have kept this separate from other reds derived from woods, because
it is said (by Professor H. Dussance) to be obtainable not only equal in
beauty and brightness to carmine, but of greater permanence. The process
of preparation is as follows:--The powdered root exhausted by alcohol
gives a solution to which hydrated oxide of lead is added in excess. The
combination of colouring matter and lead oxide is then collected on a
filter, washed with alcohol, dried, dissolved in acetic acid, and mixed
with a quantity of water. The red being insoluble therein is
precipitated, while the acetate of lead remains dissolved. After being
washed, the colour is dried at a low temperature. The Professor affirms
that the red so produced is unaffected by sulphuretted hydrogen, or by
light and air; and it is stated that the colour which was used to paint
the carriages of the Emperor Napoleon, remained as bright at the end of
nine years as when it was put on. Possessing such properties, it is
curious that the red has never been--in this country at
least--introduced as an artistic pigment, the more especially as
seventeen years have elapsed since its discovery.