44 Proceedings of the Royal Society 
dyes of the class of which Orchil, Cudbear, and Litmus 
are the familiar types. 
II. The families, genera, or species that possess practical colorific 
value; as well as the relative values of colorific species or 
varieties. 
III. The irregularities or uncertainties of colour-development, 
according to 
(a) The condition of the lichen operated on ; 
( b ) The condition of the reagent ; or 
(c) The circumstances of experiment. 
There is thus a rough indication, on the one hand, of the so-called 
Dye-lichens ; and, on the other, of species and genera that are practi- 
cally useless to the colour-maker. 
The present series of experiments, moreover, has a direct prac- 
tical bearing on 
I. The recent introduction of Colour-tests as Specific Characters in 
Lichens ; 
II. The modern manufacture from Lichens (e.y., in France) of 
fast dyes , capable of competing successfully with the brilliant 
coal-tar colours and other dyes of recent introduction ; and 
III. The use, which still lingers in certain parts of Scotland, and 
probably also of W ales and Ireland, of lichens as Domestic 
dye-stuffs. 
2. On the Principles of Scientific Interpretation in Myths, 
with Special Beference to Greek Mythology. By Pro- 
fessor Blackie. 
Professor Blackie commenced by saying that, of all the branches 
of interesting and curious learning, there was none which had been 
so systematically neglected in this country by English scholars as 
mythology — a subject closely connected both with theology and 
philosophy, and on which those grand intellectual pioneers and 
architects, the Germans, had expended a vast amount of profitable 
and unprofitable labour. The consequence of this neglect was, 
that of the few British books we had on the subject, the most 
noticeable were not free from the dear seduction of favourite ideas 
which possessed the minds of the writers as by a juggling witch- 
