674 



PRACTICE OF AGRICULTURE. 



Part III. 



neighborhood ; and on these accounts are sometimes worth the trouble of collecting. 

 They may be removed, with the least inconvenience, when the land is fallowed. Where 

 loose stones are of a moderate size, they are sometimes found advantageous rather than 

 detrimental, as in the stone-brash soils of Somersetshire and other districts. They pre- 

 vent evaporation, and thus preserve moisture in the soil. Hence the old remark, that 

 farmers have been induced to bring back again to their corn-fields those very stones they 

 have been induced to carry off. (Code.) 



4167. Where stones are large and fixed in the earth, if they appear above the surface, 

 they should be removed before the ploughing of the waste commences : but where they 

 are concealed under the surface, various modes to get rid of them have been adopted. 

 In some parts of Yorkshire, the whole surface is gone over with sharp prongs, which, at 

 the distance of every twelve or fourteen inches, are thrust into the ground to the depth 

 of about a foot, to ascertain where stones are to be met with. The spot is marked by a 

 twig, and the stones are removed before the land is ploughed. Sometimes the plough is 

 used without such previous examination, and the place marked where stones are en-r 

 countered, that they may be taken away ; and sometimes, in order to discover and re- 

 move such stones, the land is trenched by the spade. (^Communications to the Board of 

 Agr. vol. ii. p. 253.) 



41 6S. Stones above the surface may be avoided by the ploughman, though not without 

 loss of ground ; but stones under the surface are often not discovered till the plough is 

 drawn against them, and perhaps broken, by which a day's work is sometimes lost. A 

 wooden bolt, however, to unite the horse-trees to the chain of the plough, may prevent 

 mischief by giving way. Clearing the ground from stones not only prevents such mis- 

 chiefs, but is attended with actual profit. When removed, they may be used for various 

 purposes, and are often less expensive than if dug, or purchased at a quarry. The soil 

 round a large stone is likewise, in general, the best in the field, and is bouglit at a low 

 rate by the expense of taking out the stone, as the plough has thus access to all the land 

 around it. In stoney land the plough must proceed slowly, and cannot perform half so 

 much work as it ought to do ; but, after such impediments have been removed, the field 

 may be ploughed with the usual facility and cheapness, and in a much more perfect 

 manner. It frequently happens, that when working stoney land, more expense is in- 

 curred in one season by the breaking of ploughs, besides the injury done to the horses 

 and harness, than would cure the evil. {Gen. Rep. of Scot. vol. ii. p. 2^6; Kaimes^ss 

 Gent. Farmer y p. 58.) ' 



4169. There are various modes of getting rid of stones. They are 

 generally of such a size as admit of their being conveyed away in 

 carts, or other vehicles calculated for that purpose. Some ingenious 

 artificers have constructed machines for raising them, when of a large 

 size. On some occasions, pits have been dug close to large stones, 

 and the latter have been turned into the former, at such a depth 

 as to lie out of the reach of the plough. But it is frequently necessary 

 to reduce their size by the force of gunpowder before they can be re- 

 moved. Loose stones are commonly moved by levers, and rolled on a ^ 

 sledge ; but sometimes they are raised by a block and tackle attached to 

 a triangle with a pair of callipers to hold the stone (Jig. 539.). The 

 stone may also be raised by boring a hole in it obliquely and then in- 

 serting an iron bolt with an eye (Jig. 540.), which though loose will yet 

 serve to raise the stone in a perpendicular direction. 



540 4170. The mode of bursting or rending rocks or 



stones by gunpowder, is a simple, though dangerous 

 operation. When a perforation or hole is to be made 

 in a rock or stone for the purpose of blasting witli 

 ^gunpowder, the prudent workman considers the 

 nature of the rock, and the inclination or dip of the 

 strata, if it is not a detached fragment, and from 

 these determines the calibre, and the depth and direc- 

 tion of the bore or recipient for the gunpowder. 

 According to circumstances, the diameter of the hole 

 varies from half an inch to two inches and a half, the 

 depth from a few inches to many feet, and the direc- 

 tion varies to all the angles from the perpendicular to the horizontal. The implements 

 for the performance of this operation are rude, and so extremely simple and familiar, as 

 hardly to require description ; and the whole operation of boring and blasting rocks is so 

 easily performed, that, in the space of a few weeks, an intelligent laborer may become an 

 expert quarrier. 



4171. The operation of ramming frequently gives rise to accidents, but a recent im- 

 provement, that of using a wadding of loose sand, or of any earthy matter in a dry state. 



