ject, we shall find a further explanation when we examine the
diagrams showing the "direct dyes" obtained from coal tar. According
to their mode of application I have here arranged them in three large
groups, viz., basic, acid, and Congo colors. A fourth group,
comprising comparatively few, is made up of those colors which are
directly produced upon the fiber itself.

The "basic colors" have a well known type in magenta. They are usually
applied to wool and silk in a neutral or slightly alkaline bath; on
cotton they are fixed by means of tannate of antimony or tin. The
"acid colors" are only suitable for wool and silk, to which they are
applied in an acid bath. A typical representative of this group is
furnished by any one of the ordinary azo scarlets which in recent
years have come into prominence as competitors of cochineal. The
"Congo colors" are comparatively new, and are conveniently so named
from the first coloring matter of the group which was discovered,
viz., Congo red. They are applicable to wool, silk, and cotton,
usually in a neutral or slightly alkaline bath. Of the dyes produced
directly upon the fiber itself, one may take aniline black and also
primulin as a type, the latter a dye somewhat recently introduced by
Mr. A.G. Green, of this city.

Our first impression, in looking at these "direct dyes," is that they
are more numerous and more brilliant than the "mordant dyes," and that
they are for the most part fugitive. Still, if we examine the
different series in detail, we shall find here and there, on the
different fibers, colors quite equal in fastness to any of the
"mordant dyes."

Among the "basic colors" we search in vain, however, for a really fast
dye on any fiber. Still, Magdala red, perhaps, appears faster than the
rest on silk, and among the greens and blues we find a few dull blues
on cotton, which, for this fiber, have been recommended as substitutes
for indigo, viz., Indophenin, paraphenylene, blue, cinerein, Meldola's
blue, etc. The azine greens, also, appear tolerably fast on cotton and
on silk, but although possessing some body of color, after exposure,
the original dark green has changed to a decided drab.

When we examine the "acid colors," however, we meet with a number of
scarlets, crimsons, and clarets, possessing considerable fastness both
on wool and on silk. Some, indeed, appear almost, if not entirely, as
fast as cochineal scarlet, e.g., Biebriech scarlet, brilliant crocein,
e