230 W. Lauder Lindsay’s Haperiments on the 
VIII. Westring’s triple division of lichens according to the 
fixability or permanence of the colours they yield with or 
without mordants, &e. ; and his quadruple division, according 
as these colours are extractable by cold, lukewarm, hot, or 
boiling water, aided or not by various accessories, are incon- 
sistent and unnatural, and therefore not to be commended or 
followed. . 
IX. Westring’s test of colorific power is inferior to Helot’s 
or Stenhouse’s ; but all are frequently fallacious, and are far 
from being applicable in all cases. Itis probable that differ- 
ent alkalies and reagents are suitable in different cases for 
the elimination of colouring matters. 
X. The same circumstances, which modify the develop- 
ment of these colours on the small scale, cause material al- 
terations in the results of manufacture. The result, however, 
is not always proportionate to the nature and amount of the 
modifying cause, insignificant circumstances frequently giving 
rise to most important and opposite changes. 
XI. Speaking generally, the same process is equally ap- 
plicable to the evolution of the red colouring matters of all 
lichens ; but it is equally true that slight modifications of the 
process may cause a great variety in the degree or tint in any 
given species. 
XII. The chief tint educible from lichens, which can be 
of any permanent utility in the arts, is red: ore is also 
useful in a minor degree. 
XIII. Chloride of lime and aqua-ammoniz are only suit- 
able for the development of a red colour—or more strictly of 
colorific and colourless principles capable of conversion into 
red colouring matters. 
XIV. Chloride of lime is not uniformly to be relied on as 
a lichen colorimeter ; for Table xii. shows— 
a. That the alcoholic solution of certain species may 
strike no blood-red colour with that reagent, and 
still yield beautiful red and purple colours on ammo- 
niacal maceration ; and 
b. Table xiii. shows that though the alcoholic solution 
of some species do strike this colour (blood-red), it 
does not follow that ammoniacal maceration produces 
the same or a similar colour, or any colour at all. 
