ARCHIL 205 



Kane found archil and litmus of commerce to contain two classes of colouring- 

 matters, as already stated, orcine and orceinc, derived from it. Beyond these there 

 were two bodies, one containing nitrogen, azoerythrine, and the other destitute of 

 nitrogen, erythroleic acid. This latter acid is separated from the other bodies present 

 in archil by means of ether, in which it dissolves abundantly, forming a rich crimson 

 solution. It gives with alkalis purple liquors, and with earthy and metallic salts 

 coloured lakes. 



I3eyoud those already named there are several other species of lichen which might 

 be employed in producing an analogous dye, were they prepared, like the preceding, 

 into the substance called archil. Hellot gives the following method for discovering 

 if they possess this property. A little of the plant is to be put into a glass vessel ; it is 

 to bo moistened with ammonia and lime-water in equal parts; a little muriate of 

 ammonia (sal-ammoniac) is added, and the small vessel is corked. If the plant be of 

 a nature to afford a red dye, after three or four days the small portion of liquid which 

 will run off on inclining the vessel, now opened, will be tinged of a crimson red, and 

 the plant iteelf will have assumed this colour. If the liquor or the plant does not 

 take this colour, nothing need bo hoped for ; and it is useless to attempt its prepara- 

 tion on the great scale. Lewis says, however, that he has tested in this way a great 

 many mosses, and that most of them afforded him a yellow or reddish-brown colour ; but 

 that he obtained from only a small number a liquor of a deep red, which communi- 

 cated to cloth merely a yellowish-red colour. 



Prepared archil gives out its colour very readily to water, ammonia, and alcohol. 

 Its solution in alcohol is used for filling spirit-of-wine thermometers ; and when these 

 thermometers are well freed from air, the liquor loses its colour in some years, as 

 Abb6 Nollet observed ; but the contact of air restores the colour, which is destroyed 

 anew, in vacua, in process of time ; but the watery infusion loses its colour, by the 

 privation of air, in a few days ; a singular phenomenon, which merits new researches. 



The infusion of archil is of a crimson bordering on violet. As it contains ammonia, 

 which has already modified its natural colour, the fixed alkalis can produce little 

 change on it, only deepening the colour a little, and making it more violet. Alum 

 forms in it a precipitate of a brown red ; and the supernatant liquid retains a yellow- 

 ish-red colour. The solution of tin affords a reddish precipitate, which falls down 

 slowly ; the supernatant liquid retains a feeble red colour. 



The researches on the lichens, as objects of manufacture, by Westring, of Stock- 

 holm, are worthy of attention. He examined 150 species, among which he found 

 several which might be rendered useful. He recommends that the colouring-matter 

 should be extracted in the places where they grow, which would save a vast expense 

 in curing, package, carriage, and waste. He styles the colouring substance itself 

 cudbear, persio, or turnsole ; and distributes the lichens as follows : 1st. Those which, 

 left to themselves, exposed to moderate heat and moisture, may be fixed without a 

 mordant upon wool or silk; such are the Lichenes cinereus, amatonta, ventosus, 

 corallinus, Westringii, saxatilis, conspassus, barbatus, plicatus, vulpinus, &c. 



2. Those which develop a colouring-matter fixable likewise without mordant, but 

 which require boiling and a complicated preparation ; such are the Lichenes subcarneus, 

 dillenii, farinaceus, jubatus, furfuraceus, pulmonareus, comigatus, cocciferus, d'ujitatus, 

 ancialis, aduncus, &c. Saltpetre or sea-salt is requisite to improve the lustre and 

 fastness of the dye given by this group to silk. 



3.. Those which require a peculiar process to develop their colour, such as those 

 which become purple through the agency of stale urine or ammonia. Westring em- 

 ployed the following mode of testing : He put 3 or 4 drachms of the dried and 

 powdered lichen into a flask, moistened it with 3 or 4 measures of cold spring water, 

 put the stuff to be dyed into the mixture, and left the flask in a cool place. Some- 

 times he added a little salt, saltpetre, quicklime, or sulphate of copper. If no colour 

 appeared, he then moistened the lichen with water containing ^th of sal-ammoniac and 

 i^th of quicklime, and set the mixture aside in a cool place from 8 to 14 days. There 

 appeared in most cases a reddish or violet coloured tint. Thus the Lichene cinereus 

 dyed silk a deep carmelite and wool a light carmelite ; the L.physodes gave a yellowish- 

 grey ; the pustulatus, a rose red ; sanguinarius, grey ; tartareus, found on the rocks of 

 Norway, Scotland, and England, dyes a crimson-red. Cudbear is made from it in 

 Jutland by grinding the dry lichen, sifting it, then setting it to ferment in a close 

 vessel with ammonia. The lichen must be of the third year's growth to yield an 

 abundant dye ; and that which grows near the sea is the best. It loses half its weight 

 by drying. A single person may gather from 20 to 30 pounds a day in situations 

 where it abounds. No less than 2,239,685 pounds were manufactured at Christiansund, 

 Flekkefiord, and Fakrsund, in Norway, in the course of the six years prior to 1812. 

 Since more solid dyes of the same shade have been invented, the archil has gone much 

 into disuse. 



