488 DYES AND COLORING STUFFS. 



3. Moisture, &c. 4. Atmospheric vicissitudes. 5. Season of the year. 6, 

 Nature of the Gonidic reproduction (i.e., gemmation). 7. Nature of habitat. 

 8. Organic decomposition. 9. Coalescence of parts, monstrosities, &c. 



Under the second section, he traced historically the manufacture of Lichen- 

 dyes, and the native use of Lichens as dye agents, among different nations, from 

 the times of Theopl.rastus, Dioscorides, and Pliny, down to the present day, 

 sketching briefly the ancient and modern history of orchil, cudbear, and 

 litmus, and specifying the native use of lichen-dyes in different countries of 

 Europe, Asia, and America. He alluded more particularly to their application 

 to the dyeing of yarns, &c., by the Scotch Highlanders, under the name of 

 " Crottlcs." " The process of the manufacture of the various crottles, generally 

 consisted in maceraling the powdered lichen for two or three weeks, in 

 stale urine, exposing the mass freely to the air by repeated stirring, and adding 

 lime, salt, alum, or argillaceous and other substances, either to heighten the 

 color or impart consistence. To such an extent did this custom at one time 

 prevail, that, in several of our northern counties each farm and cottage had 

 its tank or barrel of putrefying urine, a homely but perfectly efficient mode of 

 generating the necessary amount of ammonia. In the county of Aberdeen, in 

 particulai, every homestead had its reservoir of "Graith,"* and the "Lit-pig,"f 

 which stood by every fireside, was as familiar an article of furniture in the cota 

 of the peasantry, as the " cuttie-stool," or the "meal girnel." So lately as 1841 

 (and I presume the practice continues to the present day), Mr. Edmonston stated 

 that, of four or five native dyes, used by the Shetlanders to color cloth and 

 yarns, two at least were furnished by lichens, viz., a brown dye from Parmelia 

 saxatilis, under the name of "Scrottyie," and a red one from Lecanora tartarea, 

 under that of " Korkalett." It is very probable, however, that steam and free 

 trade have gradually dispelled this good old custom, even in the remoter corners 

 of our island ; machinery-made articles being now readily supplied, at a rate 

 so extraordinarily cheap, as to render it absolutely expensive (as to time, if not 

 also as to money) to prepare colors, even by a process so simple and inexpensive 

 as that just mentioned." 



Under the third head, he examined, in a general way, the chemistry of the 

 colorific and coloring matters of the lichens and the rpsults to which it has led, 

 avoiding as much as possible the technicalities inseparable from such a subject, 

 and giving a short vise of the researches of Heeren, Kane, Rochlcdcr, and Heldt, 

 Stenhouse, Schunck, Laurent, and Gerhardt, and others. " Our untaught 

 senses should undoubtedly lead us to expect the lichens, whose thallus exhibits 

 the brightest tints, to yield the finest dyes, and these, too, of a color similar to 

 that of the thallus, but experience teaches us that the beautiful reddish or 

 purplish coloring-matters are producible in the greatest abundance by the very 

 species from which we should least expect to derive any, viz., in those most 

 devoid of external color. This, though at first sight very remarkable, is easily 

 explicable, when we remember that, in most of the so-called dye-lichens, 

 colorific principles exist in a colorless form, and only become converted into 

 colored substances under a peculiar combination of circumstances. 



" Some lichens contain coloring matters, ready formed, and these exhibit 

 themselves in the tint of the thallus of the plants, e.g. chrysophanic [or parie- 

 tinic] acid in Parmelia parictina, and vulpinic acid in Evcrnia vulpina. In other 

 species we find principles, which, while in the plant, and unacted on by chemical 

 re-agents, are colorless, but which, when the lichens are exposed to the com- 

 bined influence of atmospheric air, water, and ammonia, yield colored substances. 

 This series of colored products is usually comprehended more for convenience 

 sake than on account of chemical identity, under the generic term orceine." 



The whole subject of the chemistry of these bodies is at present in a most un- 

 satisfactory condition, demanding fresh investigation and research, in illustration 

 of which, the author exhibited tables of the colorific and coloring principles, so 

 far as they are at present known, showing their chemical formula? and the 



* The vernacular name for stale or putrid urine. 



"Lit" was the name applied to the plant, from which the dye was to bo prepared and 

 pitf ' is the (Scotch synonym for any kiud of earthenware vessel in which the maei-ratiou 

 TViis generally carried on. 



