EUCALYPTUS TBEES. 85 



of charcoal. It may be made in mounds, caverns, or 

 ovens. The method most frequently adopted is that 

 in mounds or meilers, and to this I may devote a few 

 explanatory words, as not every one in this hall may 

 be conversant with the process; for, simple as the 

 process does appear, it is, after all, not performable 

 without some skill, if coal of a superior quality is to 

 be the result. The wood is closely packed around a 

 central post in regular form, the pieces either all hor- 

 izontally, or, oftener, the lower vertically. Only such 

 wood should be used as is unfit for timber ; it must, 

 however, be of one kind only, or of such various sorts 

 as require the same degree of heat for being converted 

 into a perfect coal. It must be sound and almost air- 

 dry. A loamy sand - soil forms the best base for a 

 mound ; and this soil requires to be broken up, lev- 

 eled and pressed, also dried by branchlets being burnt 

 on the ground. The form of the mound or meiler is 

 usually hemispherical, and support is given to this 

 mound in the manner indicated in the sketch here 

 presented, the outer support consisting of short logs 

 of wood. 



The inner part of the cover is formed of sods of 

 grass, branchlets, rushes, and similar substances ; over 

 this is placed the outer portion of the cover, consist- 

 ing of moist forest -soil, particularly fresh humus. 

 The united covering must permit the vapors of the 

 glowing meiler to escape. Shelter against wind is 

 absolutely requisite ; the operation of burning coal can 

 therefore be well performed only in still air. The 

 ignition commences from an opening left purposely, 

 either at the base or, less frequently, at the summit 

 of the structure, but either opening is closed again 



