736 



PRACTICE OF AGRICULTURE. 



Part III 



it passes through soft strata ; in this case, a second kirb of a smaller size is sometimes begun within the 

 first. When a kirb will not sink from the softness of the strata, or when it is required to stop out water, 

 the bricks or stones must be laid one by one at the bottom of the work, taking care that the work is not 

 left unsupported in such a manner as to let the bricks fall as they are laid : this is called under-pinnmg. 



4480. Noxious air. Well-diggers experience sometimes great difficulty from a noxious air which tills 

 the well, and suffocates them if they breathe it. The usual mode of clearing wells of noxious air is, by 

 means of a large pair of bellows, and a long leathern pipe, which is hung down into the well to the bottom 

 and fresh air forced down by working the bellows. 



4481. The use of the auger is common in well-digging, both in ascertaining before commencement the 

 nature of the strata to be dug into, and also in course of digging for the same purpose ; and because, by 

 boring in the bottom of a well to a considerable depth, the spring is sometimes hit upon, and digging ren- 

 dered no longer necessary. 



4482. The use of the borer alone may procure an adequate supply of water in particular situations. This 

 mode appears to have been long resorted to in this and other countries. From what we have already 

 stated as to the disposition of strata, the conditions requisite for its success will be readily conceived ; 

 viz. watery strata connected with others on a higher level : the pressure of the water contained in the 

 higher parts of such strata on that in the lower will readily force up the latter through any orifice, how- 

 ever small. All that is necessary, therefore, is to bore down to the stratum containing the water, and, 

 having completed the bore, to insert a pipe, which may either be left to overflow into a cistern, or it may 

 terminate in a pump. In many cases, water may be found in this way, and yet not in sutficient quantity 

 and force to rise to the surface ; in such cases a well may be sunk to a certain depth, and the auger-hole 

 made, and the pipe inserted in it in the bottom of the well From the bottom it may be pumped up to 

 the surface by any of the usual modes. 



4483. As an exa?nple of well-digging combined with boring, we give that of a well dug at a brewery at 

 Chelsea, Middlesex, in 1793. The situation was within 20 or 30 feet of the edge of the Thames, and the 

 depth 394 feet, mostly through a blue clay or marl. At the depth of nearly fifty feet a quantity of loose 

 coal, twelve inches in thickness, was discovered : and a little sand and gravel was found about the same 

 depth. The well-digger usually bored about ten, fifteen, or twenty feet at a time lower than his work as 

 he went on ; and on the last boring, when the rod was about fifteen feet below the bottom of the well, the 

 man felt, as the first signal of water, a rolling motion, something Uke the gentle motion of a coach passing 

 over pavement : upon his continuing to bore, the water presently pushed its way by the side of the auger 

 with great force, scarcely allowing him time to withdraw the borer, put that and his other tools into the 

 bucket, and be drawn up to the top of the well. The water soon rose to the height of two hundred feet. 



4484. In a case which occurred in digging a well at Dr. Darwin's, near Derby, the water rose so much 

 higher than the surface of the ground, that, by confining it in a tube, he raised it to the upper part of the 

 house. (Rees's Cyclopcedia, art Well, and Derbyshire Rep.) 



4485. The process of boring the earth for spring water has of late been practised, with 

 great success, in various parts of England, chiefly by a person named Goode, of Hunt- 

 ingdon. In the neighbourhood of London, many fountains of pure spring-water have 

 lately been obtained by these means. We may particularly name those at Tottenham, 

 Middlesex, and Mitcham, Surrey, both of which afford a continuous and abundant flow 

 of water, at one time equal to about eight gallons per minute, but now reduced to a much 

 smaller quantity, in consequence of the great number of holes that have been bored into 

 the supplying strata. 



4486. The operation qf boring for water [fig. 691.) is thus performed : The situation of the intended well 



being determined on, a circular hole is 

 generally dug in the ground, about six 

 or eight feet deep, and five or six feet 

 wide. In the centre of this hole, the 

 boring is carried on by two workmen, 

 assisted by a labourer above. (Jig. 691.) 

 The implements used may either be 

 those of Goode, already described 

 ( 2507.) as the best, or any other in- 

 struments in repute. For variety's 

 sake, we shall here describe the pro- 

 cess by the instruments formerly in 

 most general use about London. 

 The handle (^^.691.rt) having a fe- 

 male screw in the bottom of its iron 

 shank, a wooden bar or rail passing 

 through the socket of the shank, and 

 a ring at top, is the general agent, to 

 which all the boring implements are 

 to be attached. A chisel {b) is 

 first employed, and connected to this 

 handle by its screw at top. If the 

 ground is tolerably soft, the weight 

 of the two workmen, bearing upon 

 the cross-bar and occasionally forcing 

 it round, will soon cause the chisel to 

 penetrate ; but if the ground is hard 

 or strong, the workmen strike the 

 chisel down with repeated blows, so 

 as to pick their way, often changing 

 their situation by walking round, 

 which breaks the stone, or other 

 hard substances, that may happen 

 to obstruct its progress. 



4487. The labour is very con- 

 siderably reduced by means of 

 an elastic wooden pole placed 

 horizontally over the well, from which a chain is brought down, and attached to the 

 ring of the handle. This pole is usually made fast at one end as a fulcrum, by being 

 set into a heap of heavy loose stones ; at the other end the labourer gives it a slight up 

 and down vibrating motion, corresponding to the beating motion of the workmen below, 



