ON THE PRESENT USE OF LICHENS AS DYE-STUFFS. 107 
Europe are probably larger than at any previous period; but I have 
not had access to statistical details even relative to this country, and 
am therefore not prepared to state precisely to what extent such in- 
crease exists. It would appear, however, to have been coextensive 
with the multiplication of the geographical sources of supply; the 
discovery of the superior value of exotic forms ; and the process of the 
various improvements in manufacture directed to the permanency of the 
we may be guided by the testimony of the various Inter- 
national Exhibitions, including and succeeding that of 1851, the Por- 
tuguese appear to give more attention to Dye-lichens than any other 
European nation. From her colonies—especially in Central Africa— 
the exhibits are invariably comparatively numerous, and the imports 
apparently comparatively large. In the Exhibition of 1562, Portugal 
showed “ Orchella weeds ” from Angola, Benguela, Mozambique, Cape 
Verde, St. Thomas’s and Prince’s Island in Africa, as well as from 
India (Panguin), and Timor (one of the Molucca Islands). In the 
present French Exhibition similar exhibits are made; while France 
stands second in her exhibits, showing characteristically, however, al- 
most exclusively the Dyes manufactured from “ Orchella weeds,” the 
colorifie principles of these weeds and their derivatives (e. g. Orcin, 
Orceine, and Orchelline). In the Paris Exposition there are also a 
ew German and other exhibitors of Orchill or its extracts or deriva- 
tives; while Britain appears to be unrepresented either as regards dye- 
lichens or lichen-dyes. 
It is of interest to botanists and chemists, as well as to manufac- 
turers, that the latter have been led by experience to recognize very 
different tinctorial qualities of the same species from different localities, 
even of the same country or limited district (e. g. of Western Africa 
or Western South America), and still more from different countries 
(e.g. Africa and South America). For instance, the same species—some 
one of the varieties of Roccella fuciformis—which from Mozambique 
sells at £50 per ton, from Ceylon fetches only £20 to £30. Unfor- 
tunately, manufacturers have also found that it is impossible to foretell 
or estimate the colorific value of any new sample of *' Orchella weed " by 
any series of chemical or other experiments on the small scale. In all 
cases of purchase of new samples, tests on the small scale are applied, 
but they are never relied upon. Colorifie value can be determined 
only by manufacture on the large scale; and, as this is an experiment 
