FIREWOOD. 69 



qnickly, and hence do not maintain a sufficiently steady heat). 

 For the kitchen also charcoal holds the first place, both on account 

 of the even heat it gives out and for its burning without smoke. 

 Hence the exclusive use of charcoal for roasting, baking, and 

 grilling ; but when wood can be used, the choice between the soft 

 and light and the hard and heavy kinds depends on the nature of the 

 food to be cooked according as it requires a quick or a slow fire. 

 The baker, the potter, the tile and brick-maker, the lime-burner, the 

 stoneware manufacturer, &c., require a fuel that burifs readily and 

 gives up all its heat quickly, and hence prefer the softer and 

 lighter woods. For warming purposes the best adapted are the 

 heavy woods, that are not reduced to ashes at once, but form 

 large masses of glowing charcoal, and which do not crackle 

 and splutter or emit clouds of black pungent or malodorous 

 smoke. 



In the Himalayas the resin-gorged wood of pine and deodar 

 stumps is split up into chips and splinters, and burnt in a chafing 

 dish in place of a lamp, giving out both light and heat. Dry 

 bamboos, bruised so as to become full of numerous long cracks, 

 burn like torches, and are so used by night travellers through the 

 jungles. The green branches of the torch tree {Ixora parviflora) 

 are also used for torches. 



(2). Wood burnt for the products of combustion. 



When wood is burnt (dry distilled) numerous substances are 

 given off in the smoke and vapours, such as lighting gas, acetic 

 acid, wood spirits, ether, creosote, tar, pitch, soot, &c., the quanti- 

 ty of these substances increasing with the temperature to which 

 the wood is raised, i.e., with the rapidity of the distillation. In the 

 ashes, we have potash and various other salts. The woods that 

 constitute the best fuel also yield the largest quantity of acid, 

 small branch wood being the richest. Tar and pitch can be 

 obtained in remunerative quantities only from resinous conifers. 

 The destructive distillation of wood is usually effected in large 

 iron vessels connected with a condenser. Tar and pitch may be 

 easily made by heaping up the wood to be burnt in a pit, at the 

 bottom of which there is a receptacle or a hole in communication 

 with a receptacle. After being filled, the pit should be very nearly 

 closed with sods, only a small opening in the middle being left in 

 order to admit a sufficient supply to maintain the wood at a glowing 

 heat. The wood should be split up small. As the wood burns the 

 tar and pitch run down to the bottom and is thus collected. 



