PEAT BOGS AND TURBARIES. 103 



and other trees, constantly found embedded in it in a per- 

 fect State ; and," he adds, " the air of peat bogs is more 

 salubrlous in consequence." 



Peat is impervious to water in a high dcgree, and 

 retains it like clay. When dry it becomes a hard, tough, 

 and ponderous mass, and is one of the most insoluble sub- 

 stances, and least liable to decay. In Holland it is fre- 

 quently used to lay under the foundations of their houses, 

 where it remains unchanged for ages, and when the build- 

 ing has been totally decayed by time, the peat remained 

 entire. Peat contains, in 100 parts, from 60 to 80 parts of 

 matter destructible by fire, and the residuum consists of 

 earth, usually the same kind as the substratum of soil on 

 which it rests, together with a portion of the oxide of iron. 

 Kirwan, states " that a piece of dried peat was put into 

 the boiler of a steam engine for three months, yet though 

 exposed to heat greater than boiling water, it remained 

 unchanged. The only appearance it exhlbited, was that 

 the surface of it was covered over with a kind of povvder 

 of iron which attracted the magnet ; the centre and all but 

 the surface remained unchanged," 



3. The accumulation of alluvial clay and other earthy 

 matter over the peat formation is visibly ascertained in the 

 excavations made in forming new Channels for the draining 

 of these marshes, and in digging foundations for bridges, as 

 at Highbridge, in 1804, At the dej^thof seven feet in the 

 alluvial deposit, the workmen came to a Stratum of indu- 

 rated peat,* lying beneath it, and on it a heap of Roman 

 pottery in fragments, with pieces of small bricks, such as 

 are used to separate vessels in the klln when they are 

 burnt ; also, moulds for casting coins, we presume of zinc, 



• This peat so compressed is called pill-coal, being nearly as pon- 

 derous as coal. 



