100 Proceedinc/s of the Roi/al Irish Academy. 



For analysis the substance was recrystallized from acetone and dried in 

 an air oven at 110°C. In two cases the substance left a slight residue of ash 

 which was weighed and allowed for. 



The results of three analyses were as follows : — 



1. 0-1599 substance gave 0'3344 COo and 0-0596 H2O, corresponding to 



C 57-03 and H 4-14. 



2. 0-1007 substance gave 0-2090 C,0 and 0-0396 H^O (ash 0-0005), 



corresponding to C 56-88 and H 4-39, allowing for ash. 



3. 0-1136 substance gave 0-2336 COz and 0-0405 H,0 (ash 0-0005), 



- corresponding to C 56-33 and H 3-97, allowing for ash. 



These analyses agree with the formula CaiH^Ois, which requires C 56-89, 

 H 3-97. 



With regard to the identity of this substance, Zopf (Liebig's Annalen, 

 35-2 (1907), pp. 1-44 found in this lichen a compound which he named 

 scopuloric acid, and which has properties similar to those of our substance. 

 The formula given by Zopf for scopuloric acid, djHisOg requiring C 58-53, 

 H 4-11, does not agree well with the analyses of our substance, which, never- 

 theless, is probably identical with Zopf's scopuloric acid. 



The formula C'siHosOie for scopuloric acid gives, possibly, an indication of 

 a close relationship between it and salazinic acid CanHjiOie, which it resembles 

 very closely, and of which it may « ell be a homologue. In this connection it 

 is interesting to note that Zopf, who gives the formula CsHuO,,, for salazinic 

 acid, proposes ('.jHitOg for scopuloric acid, which facts might be interpreted 

 somewhat similarly, scopuloric acid being a desoxy-salazinic acid. Further, 

 the above analyses of scopuloric acid also agree with the formula CisHieOg, 

 which requires C 57-4, H 4-25, and if we take the formula CnHuOj for 

 salazinic aciti, this formula for scopuloric acid will also correspond to the 

 next higher homologue of salazinic acid. 



Fvrthev Treafment 0/ the Lichen. 



After e.xtraclion with acetone the lichen was found to contain practically 

 no substance soluble in alkali, and was not further examined. 



Dyeing Experiments. 



The lichen itself, when boiled for six hours with an equal weight of wool, 

 imparts a reddish-brown colour to the wool, this colour being similar to, but 

 not so red as that given by Farnielia saxatilis. If boiled for a shoi ter time 

 than this, the colour obtained is lighter— yellowish-brown or yellow. 



It was found that the scopuloric acid, when boiled with the wool in water. 



