wool and
silk. For cotton and linen dyeing it is not used. It is rarely used by
itself as the colour is fugitive, but by using a mordant of tin, the
colour is made much more permanent.

Many of the British lichens produce colours by the same treatment as
is used for producing Orchil. Large quantities were manufactured in
Scotland from lichens gathered in the Shetlands and Western Highlands.
This was called Cudbear. The Species used by the Scottish Cudbear
makers were generally _Lecanora tartarea_ and _Urceolaria calcarea_;
but the following lichens also give the purple colour on treatment
with ammonia:--_Evernia prunastri_, _Lecanora pallescens_,
_Umbilicaria vellea_, _U. pustulata_, _Parmelia perlata_. Several
others give colours of similar character, but of little commercial
value. The manufacture of Archil and Cudbear from the various lichens
is simple in principle. In all cases the plant is reduced to a pulp
with water and ammonia, and the mass kept at a moderate heat and
allowed to ferment, the process taking two or three weeks to complete.

RECIPES FOR DYEING WITH LICHENS

_To dye Brown with Crotal._ For 6-1/4 lbs. (100 ozs.) of wool. Dye
baths may be used of varying strengths of from 10 to 50 ozs. of
Crotal. Raise the bath to the boil, and boil for an hour. A light tan
shade is got by first dipping the wool in a strong solution of Crotal,
a darker shade by boiling for half-an-hour, and a dark brown by
boiling for two hours or so. It is better, however, to get the shade
by altering the quantity of Crotal used. The addition of sufficient
oil of vitriol or acetic acid to make the bath slightly acid will be
an improvement (a very small quantity should be used).

_To dye red with Crotal._ Gather the lichen off the rocks--it is best
in winter. Put layers of lichen and wool alternately in a pot, fill up
with water and boil until you get the desired tint. Too much crotal
will make the wool a dark red brown, but a very pretty terra cotta red
can be got. No mordant is required.

_To dye Pink from a bright yellow Lichen_ (_Parmelia parietina_).
Mordant the wool with 3% of Bichromate of Potash, then boil with the
lichen for 1 hour or more.

_To dye Brown from Crotal._ Boil the wool with an equal quantity of
lichen for 1 or 1-1/2 hours. No mordant is required.

_To dye red purple from Cudbear and Logwood._ Dye with equal
quantities of Cudbear and Logwood, the wool having been mordanted with
chrome. A lighter colour