ROUGH CONVERSION. 251 



(b) Firewood. 



After all the wood which can be used as timber has been 

 prepared, what is left is firewood. 



Firewood is stacked for measurement, and termed cord wood. 

 In Germany, Austria-Hungary and Switzerland, the usual length 

 of pieces of cordwood is one meter, or 39 inches, but this measure 

 is not compulsory, provided the volume is computed in cubic 

 meters. [In Britain the length of billets is usually 3 feet. — Tr.] 



Firewood is distinguished as follows according to the shape 

 and size of the pieces : — 



i. Sjylit Billets. 



Split firewood comes from stems and branches measuring 

 across the smaller ends at least 5^ inches (14 centimeters), in 

 Switzerland, 4i inches (12 centimeters). 



A piece of split firewood should measure from 54-8 inches 

 (14 to 20 centimeters) along the chord of its larger end, and 

 exceptionally up to 11 inches (28 centimeters), and should 

 always be split from the core of the tree. 



ii. Hon lid Billets. 



Round firewood billets are unsplit round pieces of wood 2^-5^ 

 inches (7 — 14 centimeters), in diameter at the thin end. In 

 many districts, ■\\ood of this class is split in half. Round pieces 

 of larger dimensions are sometimes used in charcoal-making. 



It is always advisable to split the round pieces of firewood, in 

 order to ensure drying, reduce carriage and increase the heating 

 power of the wood. Experiments have shown that round fire- 

 wood when split loses 27-28 per cent, more weight in the five 

 winter months than unsplit wood, and Schuberg has proved 

 experimentally that its loss in weight in four weeks' time is 

 double that of unsplit firewood. 



iii. Stiiiiij)- (Did Root-wood. 



Pieces of stumps and roots of all sizes, provided they are not 

 longer than the other pieces of cordword and may thus be 

 conveniently stacked, form this class of firewood. 



