38 USES OF LICHENS. 



soil is produced, for the nourishment of the luxuriant herbage, 

 and the support of the lofty forest-tree. And thus, by the 

 labours of these apparently insignificant plants, Men are enabled 

 to reap their harvest, and to supply themselves with timber from 

 forests, and cattle increase and multiply, on what was formerly 

 but a naked and desolate rock. 



38. One of Nature's truest though least attractive delineators, 

 has thus faithfully described such a process, as it occurs on ruined 

 buildings. It should be remarked, however, that the terms seed, 



foliage, and flower, are not strictly correct as applied to the 

 Lichens, which have none of these. 



" Seeds to our eyes invisible, will find 

 On the rude rock the bed that fits their kind ; 

 There in the rugged soil they safely dwell, 

 Till showers and snows the subtle atoms swell, 

 And spread th' enduring foliage ; then we trace 

 The freckled flower upon the flinty base ; 

 These all increase, till in unnoted years 

 The stony tower as gray with age appears, 

 With coats of vegetation thinly spread, 

 Coat above coat, the living on the dead. 

 These then dissolve to dust, and make a way 

 For bolder foliage, nursed by their decay : 

 The long-enduring ferns in time will all 

 Die and depose their dust upon the wall : 

 Where the wing'd seed may rest, till many a flower 

 Shows Flora's triumph o'er the falling tower." 



CRABBE'S Borough. 



39. Besides this important office in the economy of Nature, 

 some of the Lichens are peculiarly useful to man, on account of 

 the valuable dyes they afford him. The blue dye termed Archil, 

 or Litmus, which is changed to a bright red by the action of 

 acids, is obtained from several species of Lichen growing in the 

 Canary Islands and elsewhere ; and many other species, not at 

 present regarded, might probably be converted with advantage 

 to the same use. To the Laplanders, the tribe of Lichens is of 

 peculiar utility ; indeed on it they depend for their subsistence. 

 For though it is not an article of their own diet, a humble 

 Lichen, commonly known as the Reindeer Moss, supplies the 

 animal, on which they depend for almost all their means of ex- 



