232 W. Lauder Lindsay’s Haperiments on the 
1. Parmelia, 5. Solorina, 9. Lecidea, 
2. Sticta, 6. Scyphophorus, 10. Peltidea, 
3. Cetraria, 7. Stereocaulon, 11. Collema, 
4, Nephroma, 8. Borrera, 
some of which furnish good brown colours. 
XIX. Among the general results of my experiments it ap- 
peared that of 540 specimens examined, 
22 Gave rich purple or red colours to ammonia plone (t.e., by 
simple maceration). 
8 Gave rich brown colours to ammonia alone. 
93 Alcoholic solutions gave rich purples or red on the addition 
of ammonia. 
81 Alcoholic solutions gave well-marked brown on the addition 
of ammonia. 
127 Alcoholic solutions gave well-marked orange on the addition 
of ammonia. 
42 Alcoholic solutions gave well-marked greenish-yellow on the 
addition of ammonia. 
79 Alcoholic solutions struck a deep blood-red with solution of 
chloride of lime. 
XX. The whole subject of the intimate chemistry of the 
lichen colouring matters is in a very unsatisfactory condition, 
demanding reinvestigation ; and I therefore repeat, that 
the branch of the Natural History of the Lichens, to which, 
in this and previous papers, I have endeavoured to draw 
scientific attention, will form a worthy object of research to 
the botanist and chemist, and possibly a remunerative one to 
the wholesale manufacturer. 
[lf commanders and masters of ships were aware of the 
value of these plants, which cover many a rocky coast and 
barren island, they might, with a slight expenditure of time — 
and labour, bring home with them such a quantity of these 
insignificant looking plants as would realize considerable 
sums, to the direct advantage of themselves and the ship- 
owners ; and consequently to the advantage of the state. It 
is with the view of inciting those to whom the opportunity 
may offer, of gathering a valuable article of commerce, the 
value of which they would little suspect from its external 
aspect, and inducing the owners of vessels to direct the at- 
tention of their officers to this subject, that I subjoin some 
simple methods (says Dr Lindsay) of detecting the various 
Lichens.] 
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