Book IV. SWING PLOUGHS. 391 



for, if we make it more oblique, it causes the plough to choke up with stubble and 

 grass roots, by throwing them up against the beam ; and, if less oblique, it is apt to drive 

 the stones or other obstacles before it, and make it heavier to draw. 



2596. The mould-board, for all free soils, and for working fallows, is generally most 

 effective when it has a considerable concavity ; but for breaking up clover leys, pasture, 

 or any firm surface, and also for clayey soils, it is found to clean itself better and make 

 neater work when it approaches nearer to a plane, and in very stiff clays, is formed with 

 a concave surface. The lower edge of the mould-board, on the most improved forms, 

 is in a separate piece, which, when it wears, can be taken off and renewed. The tech- 

 nical name of this slip of iron is the wealing piece. 



2597. The materials with which ploughs are constructed is, generally, wood for the 

 beam and handles, cast-iron for the head, side-plates, mould-board, and sole, and wrought 

 iron for the share, coulter, and muzzle. But of late years, in consequence of the dear- 

 ness of timber, and the cheapness of iron, they have been constructed wholly of the latter 

 material, and with considerable advantage in point of strength and durability, and some 

 also in point of convenience. Among the conveniences may be mentioned, the facility 

 which they afford of bending the left handle to the right of the straight line' (see 



Jig. 293. a), first introduced by Mr. Wilkie of Uddingston, (who, if not the inventor, may 

 certainly be considered the greatest improver of iron ploughs,) by which means the 

 ploughman is permitted to walk with ease in the bottom of the furrow. The stilts or 

 handles may also be joined to the body of the plough, in such a way as to admit of 

 taking off and packing for a foreign country, or raising or lowering the points of the 

 handles according to the size of the ploughman, as in Weatherley's plough. 



*2598. Of silting ploughs, by far the best is the implement known in England as the 

 Scotch plough. It is almost the only plough used in Scotland, and throughout a con- 

 siderable part of England ; it is drawn with less power than wheel ploughs, at least, 

 those of the old construction, the friction not being so great ; and it probably admits of 

 greater variations in regard to the breadth and depth of the furrow-slice. It is usually 

 drawn by two horses abreast in common tillage ; but for ploughing between the rows 

 of the drill culture, a smaller one drawn by one horse is commonly employed. A plough 

 of the swing kind, having a mould-board on each side, is also used both in forming 

 narrow ridges for turnips and potatoes, and in laying up the earth to the roots of the 

 plants, after the intervals have been cleaned and pulverised by the horse and hand-hoe. 

 This plough is sometimes made in such a manner, that the mould-board may be shifted 

 from one side to the other when working on hilly grounds ; by which means the fur- 

 rows are all laid in the same direction. This will be found described as the turn-wrest 

 plough. 



2599. String jtioughs, similar to the Scotch plough, have been long known in England. 

 In Blythe's Improver Improved (edit. 1652), we have engravings of several ploughs; 

 and what he calls the " plain plough" does not seem to differ much in its principal 

 parts from the one now in use. Amos, in an Essay on Agricultural Machines, says, that 

 a person named Lummis (whom he is mistaken in calling a Scotchman, see Maxwell's 

 Practical Husbandman, p. 191.) " first attempted its construction upon mathematical 

 principles, which he learned in Holland ; but having obtained a patent for the making 

 and vending of this plough, he withheld the knowledge of these principles from the public. 

 However, one Pashley, plough-wright to Sir Charles Turner of Kirkleathem, having a 

 knowledge of those principles, constructed upon them a vast number of ploughs. After- 

 wards his son established a manufactory for the making of them at Rotherham. Hence 

 they obtained the name of the Rotherham plough ; but in Scotland they were called the 

 Dutch or patent plough." "At length the Americans, having obtained a knowledge 

 of those principles, either from Britain or Holland, claimed the priority of the invention ; 

 in consequence of which, President Jefferson, of the United States, presented the prin- 

 ciples for the construction of a mould-board, first to the Institute of France, and next to 

 the Board of Agriculture in England, as a wonderful discovery in mathematics." (Com- 

 munications to the Board of Agriculture, vol. vi. p. 437.) According to another writer, 

 the Rotherham plough was first constructed in Yorkshire, in 1720, about ten years before 

 Lummis's improvements. (Survey of the West Riding of Yorkshire. Sup. Encyc. Brit. 

 art. Agr) We have seen it stated somewhere, that one of the first valuable alterations 

 on the swing plough, of the variety formerly used in Scotland, was made by Lady Stewart 

 of Goodtrees, near Edinburgh, grandmother to the Earl of Buchan. She invented what 

 is called the Rutherglen plough, at one time much used in the west of Scotland. 



2600. The Scotch plough was little known in Scotland till about the year 1764, 

 when Small's method of constructing it began to excite attention. (Small's Treatise on 

 Ploughs and Wheel Carriages, 1784; and Lord Kaimes's Gentleman Farmer). This inge- 

 nious mechanic formed the mould-board upon distinct and intelligible principles, and 

 afterwards made it of cast-iron. His appendage of a chain has been since laid aside. 

 It has been disputed, whether he took the Rotherham, or the old Scotch plough, for the 



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