THE MANUFACTURE OF CHARCOAL. 



required to fill, burn, and empty is about three weeks. Pit- 

 burning, for estate purposes, is, however, most commonly 

 pursued, and has this advantage that the charcoal can be 

 made at any place where timber is being felled, without 

 extra expense, save that of the cartage of the charcoal, 

 whereas in using the kiln or retort the wood must, in most 

 cases, be conveyed to the place where it is erected. 



Comparative value of woods for charcoal making. 

 Amongst home-grown timber, oak, ash, and beech are 

 generally preferred for charcoal making, but the following 

 table will show pretty correctly the proportionate relative 

 values of the various descriptions of wood for gunpowder 

 charcoal : 



Per Cent. 

 Rhamnus frangula contains ... ... ... 27 



Laburnum ... ... ... ... ... 25 



Boxwood ... ... ... ... ... ... 24 



Sweet Chestnut 23 



Oak 22 



Holly 20 



Walnut 20 



Beech ... 19 



Sycamore 19 



Elm 19 



Willow ... 18 



Poplar 18 



Birch 17 



Alder 17 



Ash ... 17 



Hazel 17 



Mountain Ash .. ... ... 17 



Scotch fir 16 



Larch ... 16 



Uses of Charcoal- The uses of charcoal for estate pur- 

 poses are very numerous, for horticultural, agricultural, and 

 other departments. From remote antiquity charcoal has 

 beon used us a fuel, and for many purposes it is still un- 

 surpassed. It is by far the cleanest solid fuel known; 



159 



