98 Proceedings of the Royal Irish Academii. 



obtained depends on the amount of lichen used, and on the time of boiling : 

 if boiled for only two or three hours, the wool is coloured yellow, or brown- 

 yellow. 



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

 imparted a similar red-brown colour to it. The acid first goes into solution 

 slowly, the solution being yellow in colour. The wool then begins to take 

 colour, the colour deepening gradually, that of the solution also deepening, 

 until when the wool is brown in colour the solution is of a similar colour, 

 and also rather turbid or opalescent. 



It was found that the stereocaulic acid extracted by ether did not behave 

 as a dye towards unmordanted wool ; but the brown vitreous substance, 

 obtained from the dark-coloured washings, dyed wool a light brown when 

 boiled with it in aqueous methylated spirit. 



Thus it is evident that the dyeing properties of this lichen are due to the 

 presence in it of salazinic acid. As salazinic acid is a colourless substance, it 

 is likely that the dye proper is some oxidation — or decomposition — product 

 of salazinic acid which is formed when the latter is boiled with water in a 

 vessel exposed to the air. 



B. — Ramalina scopulorum Ach. 

 Collection of Lichen for Examination. 



This lichen was collected in Howth, where it is found in abundance in 

 certain localities. As already mentioned there occurs in Howth another 

 lichen — Ramalina cuspidata — which is morphologically similar to Ramalina 

 scopulorum, but, according to Miss Knowles (Sci. Proc. E. Dub. Soc, vol. xiv 

 (N.S.), Xo. 6, p. 88), Ramalina cuspidata occurs only on the western and 

 south-western (and consequently most sheltered) side of the promontory, 

 while Ramalina scopulorum is exceedingly scarce on this side, but is found in 

 abundance on the more exposed southern and eastern sides, Ravialina 

 cuspidata not being found at all on these sides. 



The lichen examined was collected in Glenaveena on the south-east of 

 Howth, and was identified by Miss Knowles as Raraalina scopulorum Ach. 



Extraction with Ether. 



The ground lichen (about 75 grams) was extracted with ether for about 

 eight hours in a Soxhlet apparatus. The extract, which was brown in colour, 

 gave a yellow crystalline substance on concentrating and cooling. This 

 substance was filtered off, washed with ether to remove brown oily matter, 

 and recrystallized from acetone, in which it is readily soluble. 



