GENERAL ACCOUNT OF PEAT. 791 



Much has been written at different times about the com- 

 position of peat ; recently, Wiegmann, Sendtner and Braun, 

 Miiller and Kamann,* all agree that it consists chiefly of 

 vegetable substances, the decomposition of which is arrested 

 by excessive moisture : the only questions still unsolved being 

 whether the exclusion of air by water alone suffices to retard 

 the decomposition of the vegetable remains, or whether the 

 antiseptic action of free humic acid is also indispensable for 

 this purpose, finally, whether frost in any way affects the 

 formation of peat. 



Since, during the formation of peat, air is excluded by the 

 presence of water in excess, the carbon contained in vegetable 

 di'ltris cannot be converted into carbon-dioxide, but plants in 

 the deeper layers of a peat-bog part with their oxygen and 

 become carbonised. 



Permanent and excessive moisture causes the formation of 

 peat, and this, according to Sendtner, may be due to : 



(a) Impermeability of the soil, when the bed of a peat-bog 

 is formed of clay, loam or marl. This is the usual cause of 

 peat-formation. 



(b) The porosity of the soil. When the sub-soil consists 

 of permeable sa*nd or gravel (as in the case of several Dutch 

 and North Gorman bogs) the situation being either on a level 

 with an adjoining lake or the sea, or slightly elevated above 

 them, the soil is maintained constantly wet by the sub-soil 

 water. 



(c) Inundations, when repeated annually and lasting for 

 some time. 



(d) Finally, certain mosses, e.f/., Sphagnum, Dicranum, 

 cause moors to form, as they become saturated with water and 

 spread centri finally from their original position. 



[Some European peat-bogs are of great age, and con- 

 tain remains of extinct animals (Irish elk, etc.), also of 

 arctic flora, dating from the close of the Glacial Period. 

 -Tr.] 



* Kiimann. " Moor u. Torr, ihre Eritstehung u. Kultur,'' 1888. Sendtner, 

 ' Vc^.'tfitionsvi'Hiiilinissc; von Siidbayern," p. 041 ; Sprengel's notes on pp. 37, 

 11, nt LC.-IJUCM-UX, ' Untersuchungen Uber die Torf raoore " ; also Braun, "Die 

 Hnmussiiure mid die fossilen Brennstoffe." Darmstadt, 18S4. 



