mordants, e.g., madder, cochineal, lac dye, kermes, viz., reds with
tin and aluminum, claret browns with copper and chromium, and dull
violets with iron.

Other dyestuffs, like camwood, brazilwood, and their allies, also
young fustic, give always fugitive colors whatever mordant be
employed; others again, e.g., weld, old fustic, quercitron bark,
flavin, and Persian berries, give fast colors with some mordants and
fugitive colors with others; compare, for example, the fast olives of
the chromium, copper, and iron mordants with the fugitive yellows
given by aluminum and tin. A still more striking case is presented by
logwood, which gives a fast greenish-black with copper and very
fugitive colors with aluminum and tin. Other experiments have shown
that the chromium and iron logwood blacks hold an intermediate
position. Abnormal properties are found to be exhibited by camwood and
its allies, with aluminum and tin, the colors at first becoming
darker, and only afterward fading in the normal manner.

When we examine the silk patterns, we find, generally speaking, a
similar degree of fastness among the various natural dyes, as with
wool; in some instances the colors appear even faster, notice, for
example, the catechu brown and the colors given by brazilwood and its
allies, with iron mordant.

On examining the cotton patterns, we are at once struck with the
marked fugitive character of nearly all the natural dyes. The
exceptions are: the madder colors, especially when fixed on
oil-prepared cotton, as in Turkey red; the black produced by logwood,
tannin, and iron; and a few mineral colors, e.g., iron buff, manganese
brown, chromate of lead orange, etc., and Prussian blue. Cochineal and