HARVESTING THE PEAT. 745 



ing off through the reeds, and after a few days it can be cut into 

 turves by means of a wooden lattice-frame as broad as the trench, 

 which is pressed down on the peat. 



The specific weight of Challeton's peat, according to Schenk 

 1-1 to 1-2, and to Dullo 1-8, is equal to that of coal. But it is 

 not suitable for fuel, as it burns like charcoal, without any 

 flame, the turves also fall to pieces in the fire and block up 

 the grate. 



(b) Dry pressure. — In this case the peat is subdivided as finely 

 as possible, thoroughly dried and pressed into turves. The 

 experiments of Exter made a few years ago at Haspelmoor near 

 Munich and some other places, give the best known results of 

 this method. The bog was superficially ploughed by a steam- 

 plough. All the refuse peat was finely subdivided, dried and 

 conveyed to the factory. It was then sifted and thoroughly 

 dried in a specially designed hot-air chamber, which it left with 

 only 10% of moisture, and was then converted into turves by a 

 powerful press. 



This product, however, did not answer the purpose intended, 

 as it fell into dust while burning, and was scarcely superior, as 

 fuel, to the best ordinary turves. 



(c) Wet pressure. — Owing to the obvious advantage resulting 

 from pressing the wet peat, and thus increasing its density, and 

 at the same time its compactness, more attempts have been made 

 in this direction than in any other. No attempt, however, to 

 press raw peat has succeeded, partly on account of the fibrous 

 nature of the peat, which caused it to swell again after the 

 pressure had been removed, and partly because the valuable 

 humus-carbon escaped Avith the water, and thus the product 

 deteriorated as a combustible. Other kinds of pressed turves 

 were too dense externally, and their interior either did not burn 

 well or else retained too much moisture. 



(d) Destruction of the structure of the peat, with or without 

 pressure. — It is now everywhere recognized that the structure of 

 the peat must be destroyed before the turves are formed, and 

 that only a moderate pressure, if any at all, is advisable. The 

 apparatus of Schlickeysen and Geysser, Gratjahn and Pilau, 

 Thecke and Sander, Weber and Mattel, are those best known for 

 this method. 



