DIGGING AND PREPARATION OF PEAT. 7^1 



Peat has been utilized from the earliest times, and owing to 

 the high price of fuel in Germany from 1840 to 1870, its 

 utilization was then considerably increased. The present low 

 price of fuel has somewhat retarded measures which were being 

 taken for improving the yield and preparation of peat, but it is 

 still largely utilized in many countries and the question of 

 converting it into improved fuel still attracts attention. 



Much has been written at different times about the com- 

 position of peat ; recently, Wiegmann, Sendtner and Braun 

 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 

 debris cannot be converted into carbon-dioxide, but plants in the 

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

 carbonised. The dark brown peaty mud imbedded between the 

 remains of the plants consists of carbon and humic acid. 



Permanent and excessive moisture causes the formation of 

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



(1) A damp climate, as in high mountainous regions. 



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

 formed of clay, loam or marl. 



(3) The hygroscopic nature of the soil. For only thus can the 

 presence of peat be explained on slopes, such as below the 

 summit of the Brocken, on the upper slopes of the Kuiebis and 

 in several places in the Alps. 



In a forest, the accumulation of masses of undecomposed 

 humus (heather-soil, alder-humus, &c.) often causes the forma- 

 tion of peat, humus being highly hygroscopic. Forest trees, 

 which have been thrown by storms, snow, &c., and thus by 

 their partial decomposition considerably increase the supply of 



* Vide : Semltner, Vegc'tatioJisverhdHnissc ron Sudhajjcrn, p. 641 ; Sprengel's 

 notes on pp. 37, 41 of Lesquereux, Untersuchunge/i iibcr die Torfmoorf, ; also 

 Braun, Die Humussdurc luid die/ossilen Brennsloffe, Darmstadt, 1884. 

 VOL. v. 3 A 



