894 On Lichens. J] No. 119. 



saxatilis, (Parmelia saxatilis, Ach.) ; L. conspassus ; L. harhatus, (Usnea hara 

 bata, Ach.); L. pUcatus, (Us?iea plicata, Acli.) ; Z. vulpmus, Hud., (Borrer 

 jiavicansy Ach.) ; &c. 



2. Those which develop a colouring matter fixable likewise without 

 mordant, but which require boiling and a complicated preparation, such 

 are L. subcarneus ; L. farinaceus, (Ramalina farinacea, Ach.) ; L. jubatus, 

 Linn. (Olectoria juhata, Ach.) ; L. fiirfuracens, ( Borrer a furfur acea, Ach.) ; 

 L. pulmo)iariuSf (Sticta pulmonaria, Hook.) ; L. cornigatus ; L. cocciferuSf 

 ( Scyphophoruscocciferus, Hook.) ; L. digitatus, ( Scyphophorus digitatus, Hook.) ; 

 Z. uncialis, (Cladonia uncialis, Hook.) ; L. aduncus, &c. Saltpetre or sea salt 

 are 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 am- 

 monia. Westring recommends the following mode of testing: he put three 

 or four drachms of the dried and powdered Lichen into a flask, moistened 

 it with three or four measures of cold spring water ; put the stuff to be 

 dyed into the mixture, and left the flask in a cool place. Sometimes he 

 added a little salt, saltpetre, quick-lime, or sulphate of copper. If no colour 

 appeared he then moistened the Lichen with water, containing one-twenti- 

 eth of sal ammoniac, and one-tenth of quick-lime, and set the mixture 

 aside in a cool place from eight to fourteen days. There appeared in 

 most cases, a reddish or violet coloured tint. Thus the L. cinereus, (Urceo- 

 laria cinerea, Ach.) dyed silk a deep carmelite, and wool a light carmelite ; 

 the L. physodes, (Parmelia physodes, Ach.) gave a yellowish gray; the L. 

 pustulatus (Umhilicaria pustulata, Schrad.) a rose red; L. sanguinarius, 

 {Lecidea sanguinarius, Ach.) gray ; L. tartareus, (Lecanora tartarea, Ach.) 

 a crimson red, &c. 



I cannot conclude these extracts without giving an account from Ure of 

 the Orcine, the name of the colouring principle of the Lichen dealhatus, Ach. 

 (Isidium paradoxum of the same author,) styled by Messrs. Turner and 

 Boner, a most beautiful production. The Lichen dried and pulverized is to 

 be exhausted by boiling alcohol. The solution filtered hot, lets fall in the 

 cooling crystalline flocks, which do not belong to the colouring matter. 

 The supernatant alcohol is to be distilled off, the residium is to be evapo- 

 rated to the consistence of an extract, and triturated with water till this 

 liquid will dissolve no more. The aqueous solution reduced to the con- 

 sistence of syrup, and left to itself in a cool place, lets fall at the end of a^ 

 few days, long brown brittle needles, which are to be freed by pressure 

 from the mother-water and dried. That water being treated with animal 

 charcoal, filtered and evaporated, will yield a second crop of crystals. 



