ppearance of blood stains.

_Parmelia omphalodes._ In Scandinavia and Scotland.
Withering asserts it yields a purple dye, paler, but more
permanent, than orchil; which is prepared in Iceland by
steeping in stale lye, adding a little salt and making it up
into balls with lime.

_P. parietina._ Common yellow wall lichen, Wag-massla
Wag-laf. England and Sweden, on trees, rocks, walls,
palings. Used to dye Easter eggs. Used in Sweden for wool
dyeing.

_P. physoides._ Dark crottle, Bjork-laf. Found in Sweden,
Scotland and Scandinavia, on rocks and trees.

_Sticta pulmonacea._ Oak lung, Lungwort, Aikraw Hazelraw,
Oak-rag, Hazel crottle, Rags. Found on trees in England,
Scotland, North of Ireland, Scandinavia. It dyes wool orange
and is said to have been used by the Herefordshire peasantry
to dye stockings brown. Some species yield beautiful saffron
or gamboge coloured dyes, e.g. _S. flava crocata, aurata_.

_S. scrobiculata._ Aik-raw, Oak rag. Found on trees in
Scotland and England.

FOOTNOTES:

[Footnote D: From an article by Dr. Lauder Lindsay on "The Dyeing
Properties of Lichens." _The Edinburgh Philosophical Journal_, July to
October, 1855.]

CHAPTER V

BLUE

INDIGO, WOAD, LOGWOOD

_INDIGO_

Indigo is the blue matter extracted from a plant _Indigofera
tinctoria_ and other species, growing in Asia, South America and
Egypt. It reaches the market in a fine powder, which is insoluble in
water. There are two ways of dyeing with Indigo. It may be dissolved
in sulphuric acid or oil of vitriol, thereby making an indigo extract.
This process was discovered in 1740. It gives good blue colours but is
not very permanent, darker colours are more so than the paler. It does
not dye cotton or linen.

The other method is by the Indigo vat process which produces fast
colours but is complicated and difficult. In order to colour with
indigo it has to be deprived of its oxygen. The deoxidized indigo is
yellow and in this state penetrates the woollen fibre; the more
perfectly the indigo in a vat is deoxidized, the brighter and faster
will be the colour. For wool dyeing the vats are heated to a
temperature of 50 deg.C. Cotton and linen are generally dyed cold.

TO MAKE EXTRACT OF INDIGO

1 lb. oil of vitriol (pure, not commercial).
2 oz. finely ground Indigo.
1/2 oz. precipitated chalk.

Mix a little of the indigo wit