the large and small
scale in different countries--with the principles on which they are founded.

VI. Nomenclature of the dye-Lichens, and of the Lichen-dyes.

VII. Botanical and commercial sources of the same.

VIII. Special applications of the Lichen-dyes in the arts.

IX. Commercial value of the dye-Lichens, and their products.

X. Geographical distribution of the dye-Lichens--with the effect of climate;
situation, &c., on their colorific materials.

Of the four first sections of his paper, the following is a very
short summary or synopsis:--

Under the first head, the author spoke of chlorophylle and various
organic and inorganic substances, which enter into the formation of
the colors of the thallus and apothecia of lichens, and of the
modifications of these colors depending on various degrees of--1.
Exposure to air and light. 2. Temperature. 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 Theophrastus, Dioscorides, and
Pliny, down to the present day, sketching briefly the ancient end
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 "_Crottles_." "The process of the manufacture of the various
crottles, generally consisted in macerating 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 particular, every homestead
had its reservoir of "Graith,"[53] and the "Lit-pig,"[5