J 2 The Scottish Naturalist. 



warranted the position assigned to them on these grounds, and 

 they have been superseded by other more trustworthy remedies. 



In 1868 a process was elaborated by Prof. Stenberg of Stock- 

 holm for the preparation of alcohol from Lichens ; and consider- 

 able quantities are obtained from this source in special distilleries 

 in Scandinavia, Finland, and Russia. 



But the most important use to which Lichens have been put is to 

 afford dyes for cloth, or for use in chemical laboratories, where lit- 

 mus paper, prepared from Orchil (Rocella tinctoria), is among the 

 tests in most frequent use. The dyes prepared from Lichens are 

 usually purple or red, less often some shade of yellow, but they 

 vary a good deal according to the details of the method employed 

 in extracting them. The best account of these dyes and of the 

 Lichens that yield them, will be found in papers by Dr. Lauder 

 Lindsay, published in the Report of the British Association for 

 1855 ; the Transactions of the Edinburgh Botanical Society for 

 1852-54; and the Edinburgh New Philos. Journal, 1854-5. The 

 dyes are obtained by steeping the plant in a solution of ammonia, 

 or spirits of hartshorn, in water. The colour is developed in this 

 mixture, and indicates the value of the Lichen. 



In the early part of this century the " Cudbear" (Lecanora tar- 

 iared) was largely gathered from the rocks and boulders on the 

 Scotch mountains, and was sold at about id per lb. to the manu- 

 facturers of the dye in Glasgow and in Leith. In this way about 

 14s or 15s per week could be earned by a man, since the plant 

 was very abundant. In addition to quantities exported, a good 

 deal was used in the Scotch Highlands and Islands, in the domestic 

 economy of the cottagers, by whom the wool was home-dyed as well 

 as home-spun. The Lichen was steeped in putrid urine, to provide 

 the ammonia, for some weeks, along with some salt or pieces of 

 kelp ; and when the desired colour had been obtained, the mass 

 was made into a paste with lime or burnt shells. The paste was 

 then rolled into balls and hung up to dry. For use the balls were 

 powdered, and boiled in water with alum to prepare the solution 

 for the thread. Dr. Lindsay found that the most valuable Lichens 

 were crustaceous, friable, whitish species, growing on rocks ; that 

 showy leafy kinds seldom gave purple dyes ; and that the colours 

 yielded by the latter were not of much use, being too undecided. 



The Lichens of most commercial value at the present time are the 

 " Orchils " (Rocella tinctoria and allied species), which are brought 



