_U. scruposa._ Rock Urceolaria. Grows on rocks in hilly districts in England.

_Usnea barbata._ Bearded Usnea. Pennsylvania and South America. On old trees. Stated to dye yarn orange.

_U. florida._ Flowering Usnea. Pale greenish yellow or reddish brown.

_U. plicata._ Plaited Usnea. On trees.

SHADES OF BROWN

_Alectoria jubata._ Horsehair Lichen, Rock hair. On fir trees in England. Pale greenish brown.

_Borrera flavicans._ Yellow borrera. On trees in Germany.

Gamboge yellow.

_Cetraria Islandica._ Iceland moss. Iceland heaths and hills. It yields a good brown to boiling water, but this dye appears only to have been made available in Iceland.

_Cetraria juniperina._ En-mossa. On trees in Scandinavia.

_Evernia flavicans._ Wolf's-bane evernia. On trees in Scandinavia. Gamboge yellow.

_Gyrophora cylindrica._ Cylindrical gyrophora. On rocks in Iceland. Greenish brown. Also G. deusta.

_G. deusta._ Scorched-looking gyrophora. On rocks in Scandinavia. Linnaeus states that it furnishes a paint called "Tousch", much used in Sweden.

_Lecanora candelaria._ Ljus ma.s.sa. On trees in Sweden.

_Lecidea atro-virens._ Map lichen. On rocks, Scandinavia.

_Lepraria chlorina._ Brimstone coloured lepraria.

Scandinavia, on rocks.

_L. Iolithus._ Viol-ma.s.sa. Sweden, on stones. Gives stones the appearance of blood stains.

_Parmelia omphalodes._ In Scandinavia and Scotland.

Withering a.s.serts 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 b.a.l.l.s with lime.

_P. parietina._ Common yellow wall lichen, Wag-ma.s.sla 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 50C. 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 with a small quant.i.ty of oil of vitriol, add a little chalk and stir well. Go on mixing gradually till all is used up. This should take an hour or two. Stir a few times each day for 4 or 5 days, adding about 1/2 oz. more of chalk by degrees. It is best mixed in a gla.s.s stoppered bottle or jar, and stirred with a gla.s.s rod. It must be kept from the air.

INDIGO EXTRACT (4 to 6 lbs. wool).

Mordant[E] 25% Alum. Stir 2 to 3 ozs. Indigo extract into the water of dye bath. The amount is determined by the depth of shade required.

When warm, enter the wool and bring slowly to boiling point (about 1/2 an hour) and continue boiling for another 1/2 hour. By keeping it below boiling point while dyeing, better colours are got, but it is apt to be uneven. Boiling levels the colour but makes the shade greener. This is corrected by adding to the dye bath a little logwood, 10 to 20 per cent which should be boiled up separately, strained, and put in bath before the wool is entered; too much logwood dims the colour. Instead of logwood a little madder is sometimes used; also Cudbear or Barwood.

INDIGO VAT (TIN) FOR WOOL

To 2 quarts of water add 1/4 lb. lime, and make hot. Then add 1 oz.

indigo pounded up with a little of the lime water; let it stand and get warmer. Pound up 1/2 oz. tin, _Stannous Chloride_, in a little lime water and add, together with 1/2 oz. zinc. Add more lime water or tin according to the state of the vat. There should be a streaky sc.u.m on the surface, and the water underneath clear with a green tinge.

Pearl ash can be used instead of lime.

HYDROSULPHITE-SODA VAT FOR WOOL

2 ozs. powdered indigo.

7 fluid ozs. Caustic Soda solution (SG 1.2).

4 pints Sodium Hydrosulphite (SG 1.1).

_The Stock Solution._--Take 2 ozs. of well pounded indigo, with enough warm water (120F.) to make a paste, and _grind_ in a pestle and mortar for 10 minutes. Empty into a saucepan, capacity 1 gallon. Take 12 fluid ozs. of water adding gradually 3 ozs. of commercial caustic soda 76 per cent. This will give a solution of SG 1.2, which can be tested with a hydrometer reading from 1000 to 2000, the 1000 representing SG 1 as for water.

Next take 5 pints water, add hydrosulphite slowly, stirring gently until a reading of 1100 is shown (SG 1.1) on the hydrometer. If the hydrosulphite be weighed beforehand and the stock of the same be kept free from damp air, or great heat, for future vats the hydrometer can be dispensed with; it is simply weighed out and added slowly to the water. If added too quickly the hydrosulphite will cake, fall to the bottom and be difficult to dissolve.

To the saucepan containing the indigo (100 per cent) add 7 fluid ozs.

of the caustic soda solution, then gradually add 3-1/2 pints of hydrosulphite solution, stirring gently for 15 to 20 minutes. Heat the saucepan to 120F. and on no account to more than 140F.--_overheating will ruin the Stock Solution_--let it stand for half an hour, then test with a strip of gla.s.s. This should show a perfectly clear golden yellow colour (turning blue in 45 secs. approx.), free from spots. If dark spots show, this indicates undissolved indigo, therefore gradually add hydrosulphite solution (2-3 fluid ozs.). Wait 15 mins.

and test with gla.s.s strip; if incorrect continue this every 15 minutes until the gla.s.s indicates clear yellow. If the Stock Solution is greenish white and turbid, undissolved _indigo white_ is present. Add then not more than a teaspoonful at a time caustic soda solution until the Stock Solution answers the gla.s.s test.