28 VEGETABLE SUBSTANCES. 



into bogs is said to be from the pen of Sir Walter 

 Scott, and it is certainly characterised by that accuracy 

 of observation and felicity of expression for which he 

 is so remarkable: 



" Extensive forests, occupying a long tract of 

 tolerably level ground, have been gradually destroyed 

 by natural decay, accelerated by the increase of the 

 bogs. The wood which they might have produced 

 was useless to the proprietors ; the state of the roads, 

 as well as of the country in general not permitting 

 so bulky and weighty an article to be carried from 

 the place where it had grown, however valuable it 

 might have proved had it been transported elsewhere. 

 In this situation the trees of the natural forest pined 

 and withered, and were thrown down with the wind, 

 and it often necessarily happened that they fell into, 

 or across, some little stream or rivulet, by the side 

 of which they had flourished and decayed. The 

 stream being stopt, saturated with standing water 

 the soil around it; and instead of being, as hitherto, 

 the drain of the forest, the stagnation of the rivulet 

 converted into a swamp what its current had formerly 

 rendered dry. The loose bog earth, and the sour 

 moisture with which it was impregnated, loosened 

 and poisoned the roots of other neighbouring trees, 

 which, at the next storm, went to the ground in their 

 turn, and tended still more to impede the current of 

 the water; while the accumulating moss, as the bog 

 earth is called in Scotland, went on increasing and 

 heaving up, so as to bury the trunks of the trees 

 which it had destroyed. In the counties of Inver- 

 ness and Ross, instances may be seen, at the present 

 day, where this melancholy process, of the conver- 

 sion of a forest into a bog, is still going forward." 



When a peat-bog or moss has begun to form, 

 there is no limit to its increase, save the pressure 

 of the water which it contains. In the part of 



