employed, with the discovery of new countries many of these fell
slowly and gradually into disuse, giving way to the newly imported
dyestuffs of other lands, which possessed some advantage, being either
richer in coloring matter, yielding brighter or faster colors, or
being capable of more easy application. Thus kermes gave way to
cochineal, woad to indigo, and so on.

Down to about the year 1856, natural dyestuffs alone, with but one or
two exceptions, were employed by dyers; but in that year a present
distinguished member of this Society, Dr. Perkin, astonished the
scientific and industrial world by his epoch-making discovery of the
coal tar color mauve. From that time down to the present, the textile
colorist has had placed before him an ever increasing number of
coloring matters derived from the same source.

Specially worthy of notice are the discoveries of artificial alizarin,
in 1868, by Graebe and Liebermann, and of indigotin, in 1878, by Adolf
Baeyer, both coloring matters being identical with the respective dyes
obtained from plants.

In view of the vast array of coal tar colors now at our disposal, and
their almost universal application in the decoration of all manner of
textile fabrics, threatening even the continued use of well known
dyestuffs of vegetable origin, it becomes of the greatest importance
to examine most thoroughly, and to compare the stability of both old
and new coloring matters.

The first point in discussing this question of fast and fugitive dyes
is to define the meaning of these terms "fast" and "fugitive."
Unfortunately, as frequently employed, they have no very definite