ON MANURES. I47 



The chief art in burning- is, to keep out the air, and keep 

 in the smoke ; which can only be accomplished by having the 

 walls made quite close, and taking care to have the tops 

 always lightly covered with clay. If the smoke should appear 

 coming out in spots here and there, cover those places with 

 sods immediately; for by thus half burning or charring the 

 earth, it is supposed that any vegetable matter which it con- 

 tains will be preserved, and that the staple of the land will not 

 suffer. In short the kilns must be carefully attended to, both 

 day and night, until the operation is completed. No rule 

 can be laid down for the size of the clods, but those first laid 

 on will burn more readily if dug up and dried a day or two 

 before: if they be properly managed, that, however, is not 

 absolutely necessary, and if once the kiln is fairly set a-going, 

 no further fuel of any kind is required; for the clay, though 

 wet, will continue to burn, unless extinguished by careless- 

 ness, as even the changes of the weather, except in very bad 

 seasons, have very little effect upon it. It may, however, be 

 proper to caution those who are not acquainted with tlie pro- 

 cess, from opening any part of the kiln in order to ascertain 

 its progress; for although, from its outward appearance, they 

 may imagine the fire to be extinguished, it yet may be burning 

 fiercely in the interior; and if the air be admitted, the mam 

 force of the fire will draw to that hole, where it will blaze 

 out, and thus the work will certainly be retarded, if not en- 

 tirely stopped. Although the process is very simple, when 

 well understood, yet, like every thing else, it requires some 

 experience, and mistakes are continually made by workmen 

 who, not being already acquainted with the practice, are apt 

 to burn the clay into lumps. It is, indeed, difficult to describe 

 the operation with sufficient accuracy to enable those who 

 have never seen it done to burn properly. 



Burning in heaps. — Another common mode of burning- 

 earth, is to dig up the surface of banks and headlands, or old 

 borders, and, when dry, to cart it to a heap. The practice 

 then is, to lay a foundation of earth, some inches thick, then 

 haulm, straw, dry weeds, and a few bushes, whins, or any thing 

 of the kind, upon which the pile is raised in the form of a cone, 

 and enclosed with a wall of turf in the manner already de- 

 scribed. When fuel is scarce, an experienced burner will 

 light a small heap, and increase it to almost any extent, by 

 pulling down part of the wall, drawing out a portion of the 

 fire, and addmg fresh earth. They are not uncommonly car- 



