Book IV. HARROWS. 391 



The tubes are placed parallei with the drills, two between the wheels of the cart, and one 

 on the outside of each wheel ; the distance of the tubes, and their height fVom the surface, 

 is regulated by hooks and chains; and the water is discharged in small streanys, through 

 twenty projecting apertures in the under part of the tubes. The tubes are suspended by 

 chains to the hooks in an iron rod, secured to the fore and back part of the frame of t!ie cart. 

 The mouth of the funnel on the top of the barrel, is covered with a wire-cloth, to prevent 

 any thing getting in to clog the apertures. As the quantity of water let out by the 

 apertures is less than what is received into the tubes, the tubes are always full ; by 

 which a regular discharge is kept up from all the apertures at the same time. As the 

 machine advances, the stream which falls from the first aperture upon the plants, is fol- 

 lowed up by a stream from all the apertures in the tube; therefore each plant must 

 receive all that is discharged from twenty apertures. 



2565. Estimate qf its operation. Supposing the barrel to contain 200 gallons, and the tubes-to be five 

 feet long, the diameter of the tubes three-eighths of an inch, and the diameter of the apertures in the tubes 

 to be one-sixteenth of an inch, 200 gallons will be discharged from 80 such apertures in two hours one-third. 

 The diameter of the mouths of the stop-cock must be equal to the diameter of the tubes. The horse going 

 at the rate of 2^ miles in one hour, in two hours and twenty minutes will go 5 miles five-sixths. The dis- 

 tance between four drills is 6 feet 9 inches ; therefore, if we suppose a parallelogram to be 6 feet 9 Inches 

 broad,and 5 miles five-sixths long, the area of this parallelogram will be 4 acres 3 roods 16 perches, which 

 will be watered by 200 gallons in two hours and twenty minutes : and in one hour it will water 2 acres 7'27 



Eerches, supposing the water to flow uniformly ; but the quantity given out upon the drills must be regu- 

 ited by the progressive movement of the machine. 



2566. In construction it is neither complicated nor expensive ; it may be erected upon the frame of a cart 

 used for other purposes in husbandry; and the barrel and apparatus maybe furnished for about six 

 pounds sterling, supposing the stop-cock and connecting-screws to be made of brass, and the tubes of copper 

 or tin. This machine may be used for other purposes ; such as the application of urine as a manure, or 

 of a solution of muriate of soda, which has been proposed for some crops. 



2567. The essential drill machines are French's for turnips, Cooke's for corn, and the 

 drill attached to a plough (2558.) for beans. 



Sect. III. Of Harrows. 



2568. The harroiv is an implement of equal antiquity with the plough, but it does not 

 appear to have undergone so much improvement as that implement ; nor, indeed, is it 

 capable of so much. The chief circumstances in which harrows have been rendered more 

 applicable and convenient, seem to be in the position and mode of fixing in the tines or 

 teeth, the direction of the bulls, and the manner in which the horses are attached in 

 drawing the implements. It has been suggested by the author of The Gentleman 

 Farmer, that no one harrow, whatever its construction may be, can be suitable for every 

 sort of soil, or can act with equal effect on such grounds as are rough and smooth, or 

 firm and loose : they must be adapted to the nature of the land, and the particular pur- 

 poses the operator has in view. It is sufficiently evident, that in the lighter sorts of land, 

 a small light harrow, with short tines or teeth, may be suflScient for the purpose ; but in 

 strong, heavy, and tenacious soils, or such as have been newly broken up from the state 

 of old leys, or from a state of nature, such as commons, moors, and wastes, a harrow 

 which has a much greater weight and longer teeth is to be preferred ; and even where 

 the land is rough and not easily reduced, as in the fallowing and reducing of strong 

 clays, two harrows combined with each other may frequently be proper and necessary, 

 in order to fully separate and break down the cloddy soil. And for these uses, it has 

 also been found better, especially where the land is stiflT, tenacious, and abounds much 

 with the roots of weeds, that the harrows should not be too thickly set with teeth ; as under 

 such circumstances, where they have a number of teeth, they not only soon fill and choak 

 up, which prevents them from working, but are confined too much to the surface, by which 

 the soil is very imperfectly broken down and reduced into a state of powdery fineness. 



2569. The harrows most generally used {Jig. 321.) are of an oblong shape, each con- 

 taining twenty prongs or tines, five or six inches long 

 beneath the bulls or bars in wliich they are inserted. It 

 is still common for every harrow to work separately ; 

 and though always two, and sometimes three, are 

 placed together, each of them is drawn by its own 

 horse. The great objection to this method is, that it is 

 scarcely possible, especially upon rough ground, to 

 prevent the harrows from starting out of their place, 

 and riding on one another. To obviate this incon- 

 venience, the exterior bulls of each are usually sur- 

 mounted by a frame of wood, raised so high as to ; ^^^- -^-i^ 



protect it from the irregular motions of its neighbor ; ''^''^^aJ,^ ^ . .. 



but in many instances they are connected by chains t!^ i ^t ^-|j ^p 



or hinges, or cross-bars, which is a preferable plan. '' d F ' * 



Another objection which has been made to the common harrow is, that the ruts made 

 by the tildes are sometimes too near and sometimes too distant from one another ; 

 but this is probably not a great fault when the soil requires io be pulverised as w ell as 



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