148 



Preparation of Charcoal. 



these, a place should be selected where the ground is dry, and a 

 little descending from the central part ; the rubbish should be care- 

 fully cleared away, the soil beaten down hard, and the greatest 

 precaution taken against the escape of fire. In Europe, the law 

 generally requires that a trench should be dug around the coaling- 

 ground, and that a sufficient supply of water shall be near. The 

 place should be well sheltered from the winds, and the soil should be 

 compact, and not so porous that air can enter through it from below. 

 594. Three stakes are first set in a triangular form, and around 

 these the wood is piled as closely as possible, and generally as cut in 

 lengths of 3 to 4 feet. It is either laid horizontally or vertically, as 

 shown in the accompanying cut, taken from Karsten's Atlas. The 



77. Vertical Section through the Centers of two Different Kinds of 

 Meilers. 



more common way is to set the wood endwise, sloping towards the 

 center, and there is usually a second course, with the top filled out 

 and made convex by wood pDed flatwise. 



595. The whole is then covered with straw, dead leaves, or sod, 

 and over this with earth, and the fire is dropped in at the top. 

 Around the bottom holes are left for the admission of air ; or some- 

 times a passage is left on one side for introducing the fire. It is 

 best to kindle early in the morning, and in fine weather, because i t 

 requires much attention at first to get the ignition begun. When 

 this is fairly established, the top is closed with sod. 



596. At first, a great deal of steam is generated, which condenses 

 on the inner surface of the cover, and especially around the base, 

 which is left open ; and explosions may occur from the admission 

 of air to the inflammable gases within, especially with dry resinous 

 woods. 



