814 DIGGING AND PREPARATION OF PEAT. 



in damp air and of falling to pieces when frozen. These 

 turves are, therefore, saleable only in the immediate neigh- 

 bourhood of the bog ; the price obtained for them, being low, 

 does not encourage an extensive working of the bog. Owing to 

 the high price of fuel which prevailed a few decades ago, the large 

 demands for industrial purposes and the extensive supplies of 

 peat available in certain districts, the question arose as to 

 whether peat might not be so improved by machinery as to 

 yield a fuel approaching coal in value. Owing to the subse- 

 quent depression in the price of fuel, the demand for manu- 

 factured peat has somewhat abated, but the industry is still 

 carried on in many places. 



In order that manufactured peat may compete with coal and 

 wood, it must be utilizable for heating boilers, preparing gas 

 and paraffin, in metallurgy, etc., and should fulfil the 

 following conditions : 



Density. The turves must not merely be dense super- 

 ficially, nor so dense at the surface that the air cannot reach 

 their interior, but be uniformly dense throughout. 



Compactness. The turves must be compact enough not 

 only to retain their shape during transport, but also while 

 being burned. 



High combustible power. During manufacture, the most 

 combustible parts of the peat must be carefully preserved, 

 especially the amorphous peat. 



Dryness. The peat must be dried thoroughly, not only 

 superficially, but also internally ; it should, as far as possible, 

 lose its great hygroscopicity and not swell considerably when 

 exposed to damp and thus become unserviceable. 



Quantity. The manufacture must be so conducted as to 

 yield large quantities of material and be independent of the 

 weather. 



The cost of production, including that of supervision, must 

 be sufficiently low to allow the material to compete with other 

 combustibles. 



The following methods have been undertaken to secure the 

 above conditions : contraction, dry pressure, wet pressure 

 and destruction of structure, with or without pressure. 



All these methods are, however, too costly to repay the 



