PROXIMATE PRINCIPLES OF SOME OF THE LICHENS. 
397 
These numbers give C36 Hjg Ojg as the formula of the acid in the Lecanora tartarea, 
which is exactly the formula of. gyrophoric acid. In fact the acid in the Lecanora 
tartarea is identical in all its properties and reactions with the acid in Gyrophora 
pustulata, so that no doubt can be entertained that both lichens contain one and the 
same colouring principle, viz. gyrophoric acid. 
The Ether Compound. 
Gyrophoric ether was also formed by boiling the acid from the Lecanora tartarea 
in strong spirits. As might have been expected, it proved also identical in compo- 
sition and properties with that obtained from the acid of the Gyrophora pustulata. 
The following are the results of its analysis : — 
I. 0-337 ga-m. ether dried in vacuo and burned with chromate of lead, gave 0 7^95 
carbonic acid and 0'191 water. 
II. 0-296 grm. gave 0-6658 carbonic acid and 0-165 water. 
Calculated numbers. 
Found numbers. 
per cent. 
I. 
II. 
C 40 
3000 
61-39 
61-46 
61-30 
H23 
287 
5-87 
6-29 
6-19 
0 16 
1600 
32-74 
32-25 
32-51 
4887 
100-00 
100-00 
100-00 
The rational formula for the gyrophoric ether from the acid in the Lecanora tartarea 
is therefore Cgg H^g 035+04 Hg O3. 
It is certainly not a little singular that the ether compounds of this whole series of 
acids, the lecanoric, the erythric, the alpha and beta orsellic acids, and here again the 
gyrophoric acid, should approach each other so closely in their general properties 
and in their per cent, composition. Mr. Schunck has been induced by this circum- 
stance to think it probable that all this class of acids are coupled acids containing 
lecanoric acid and an adjunct, and that the ethers which they yield are in fact only 
one compound, viz. lecanoric ether. Mr. Schunck’s hypothesis is, however, much 
weakened from the fact that we possess no means of reproducing lecanoric acid 
from the so-called lecanoric ether, for when any of these ethers are acted on by an 
alkali, the organic acid they contain undergoes decomposition as well as the com- 
pound itself. Besides, it appears somewhat gratuitous to infer merely from the per 
cent, composition of these ethers that they all contain lecanoric acid, and are in 
fact lecanoric ether, as any person may easily convince himself, by a few trials, that 
considerable alterations may be made on the formulae of these acids without mate- 
rially affecting the per cent, composition of their ethers. 
Brom-orcine. 
In the former paper on the proximate Principles of some of the Lichens, read 
before this Society on the 3rd of February 1848, I described a crystalline body ob- 
MDCCCXLIX. 3 F 
