PEAT. 343 



sition, and that of the drainage, as connected with time, 

 position, and climate. If it is easy to trace the whole 

 process in the Sphagnum palustre, it is not difficult in 

 all the other plants : the former being a sort of im- 

 mortal existence, through its offsets, succeeding to the 

 death of the lower portions, while the other plants add 

 annually to the heap of decomposing matter as they 

 extend upwards; perennial under new productions, or 

 reproduced, as successive annuals, from seeds. Hence 

 the increase of peat is constant, as long as there is a 

 living surface ; yet under some variations highly inte- 

 resting in rural economy. 



That of mountain peat, for example, is steady; be- 

 cause its texture allows it to receive the seeds of the 

 same plants, though the living surface should be re- 

 moved. Yet its growth is stopped by changing the 

 vegetation ; as it is by calcareous manures, by burning, 

 by the pasturage of sheep, and by the growth of larch ; 

 the three former comprising the usual processes by 

 which brown mountain land becomes green pasture. 

 The formation of marsh peat is checked by its own 

 growth upwards, gradually excluding water ; though 

 it may continue to increase, as mountain peat, under 

 somewhat different plants : as an entirely new vegeta- 

 tion, whether natural, or artificially produced, causes 

 it to terminate for ever in a grassy meadow. It is ob- 

 vious that the generation of forest peat ends after the 

 fall of the wood which is to form it, though it may 

 continue to grow as marsh peat : while that of the sea 

 and of lakes terminates with the exclusion of the water; 

 though, in each case, the process may continue by the 

 growth of marsh peat, terrestrial or marine. To the 

 formation of transported peat, there is no limit but the 

 cessation of that flow of water by which it was deposited. 



It is now easy to account for the naked and termi- 



