144 A PRACTICAL TREATISE 



yards of surface, 6 inches deep, for a single acre, or a pit of 

 proportionate size, if dug from the subsoil, many persons will 

 naturally grudge the sacrifice, though banks and headlands — 

 something, in short, in the shape of waste — may be found on 

 every farm. Every one who has the opportunity should give 

 it a fair trial ; and if tlie result should prove its efficacy, it 

 may then, indeed, be considered 'as opening a new field to the 

 prosperity of agriculture.' The following are the most approved 

 methods of preparation, when pits are dug from the subsoil; 

 but if the earth be taken from the surface, then those direc- 

 tions will be applicable which have been already given in the 

 previous chapter, under the head of 'Paring and Burning.' 



Clay-kilns. — There are two modes of burning clay com- 

 monly employed, one by kilns partly constructed of masonry, 

 and the other of sods; in both of which the earth is piled upon 

 them, instead of being placed under cover, as in a lime-kiln. 



The kiln of the former kind, described by Mr. Burroughs, 

 should be built in a pit excavated out of the ground which is 

 to be burned, and consists of an arch about 4 or 5 feet long, 3 

 wide, and 2 high, made with brick; the front close like an 

 oven, and the inside fitted to receive a strong fire of coals. 

 On the top of the arch six or eight holes are left, the size of a 

 small brick, to admit the heat passing out, which is to commu- 

 nicate to the earth laid on. When the fire is sufficiently 

 strong, the door of the kiln is to be well stopped, and the 

 earth thrown on in some degree pulverized, about six or eight 

 inches thick, so as to cover the top of the kiln, and every 

 direction round it to which the heat might communicate. In 

 this manner it is to be dressed alternately with culm and 

 earth, which are to be laid on according to the heat of the 

 fire, which is on no account to be allowed to burn too strong. 



After the kiln is once lighted, it will burn several hundred 

 bushels of earth without any additional fire inside ; and the 

 same kiln will answer for a length of time to renew the pro- 

 cess when necessary. 



Kilns constructed of masonry, although the most permanent, 

 have, however, been objected to, both because of the outlay in 

 their erection, and the inconvenience often experienced in 

 procuring workmen to build them. There is aUo this IVu-thcr 

 disadvantage, — that although when once built tliere is an end 

 of the expense, and with proper care they may be employed 

 for years, yet, if placed at any considerable distance from the 

 land to be manured, the cost of carriage will probably exceed 



