2629. The improved Scotch plough, with one or sometimes two wheels (fig. 308.), fixed near to the end of the beam, without any carriage, goes very light, and is very useful; such alterations as are necessary requiring very little time or trouble. Where two wheels

308

are employed, the plough does very well without a holder on a good tilth or light sward, where there are few stones, except at the setting in and turning out. Wheel ploughs should, however, probably be seldom had recourse to by the experienced ploughman, though they may be more convenient and more manageable for those who are not perfectly informed in that important and useful art.

309

2630. The Beverston plough (fig. 309.) was once considered a good wheel plough. It has its principle of draught given it in a very effective manner by an ingenious contrivance of iron work, in which, according to Lord Somerville, "the point of draught is perpendicularly above the point of traction, or the throat or breast where the share fits on."

2631. The Kentish and Herefordshire wheel ploughs are extraordinary clumsy implements of very heavy draught, and making, especially the former, very indifferent work. They were figured by Blythe in the beginning of the seventeenth century, and seem to have received no improvement since. The Kentish plough is generally made with a turn-wrest, in order always to turn land downwards in ploughing a hill; but this, as Lord Somerville remarks, soon renders the summit of the hill or the upper side of the field, where such a practice is persisted in, destitute of soil. A much better mode is to plough up and down the steep, or diagonally across it. In either case the double mouldboard plough, invented by His Lordship, is of singular use, as one furrow only need be taken in going up and two in coming down.

2632. The Norfolk wheel plough (fig. 310.) has a clumsy appearance, from the great

310

bulk of its wheels and their carriage; but in light friable soils it does its work with neatness, and requires only a small power of draught.

2633. Ploughs with wheels for diminishing friction are of comparatively recent date. Morton, of Leith walk, in 1813, conceived the idea of

introducing into the body of the plough a wheel about 15 inches in diameter, to act as the sole, and made several exhibitions of a plough so constructed before the Dalkeith Farming Society. (Gard. Mag. vol. v.) Wilkie, of Uddingston, brought forward a similar plough in 1814, and Plenty, of London, in 1815. Liston, of Edinburgh, a few years afterwards, brought forward a plough on the same principle; but it never came into use. Plenty's friction wheel plough has been occasionally used in England. It has two wheels under the beam, and one behind the sole; and, while the same plough with two wheels requires a power of 4 cwt., those with a third or friction wheel, as Mr. Plenty informs us, require only a draught of 3 cwt.

2634. Wilkie's single horse wheel plough (fig. 311.) was invented by the late Mr. Wilkie, and described by him in the Farmer's Magazine for November, 1814. It has the

wheel (d) placed behind the sole, which, besides considerably reducing the weight of draught, is found

to give a degree of` steadiness seldom exceeded in the use of the common plough, except when quite new, or recently repaired with a new sock and sole-shoe. At that period, when the back end of the

311

Ja

sole is quite full and square, the common plough (when well constructed) goes as well as can be wished for; but, by the great friction of the sole, the back end of it soon becomes convex, and, consequently, the plough loses the steady support of the extremity of the heel; or, in other words, in proportion as the sole becomes more convex, the fulcrum of the lever is extended considerably forward, so as to be too near the centre of gravity. When that is the case, the least obstruction at the point of the share hrows the plough out of the ground. In order to remedy or counteract that tendency, the ploughman is obliged to raise the point of draught at the end of the beam; but this expedient, although it gives the plough more hold by the point of the share, is attended with another inconvenience fully as bad as the former; for, when the point of the share meets with an obstruction as before noticed, the heel of the plough is raised, on account of the point of draught being fixed above the direct line of traction. Thus, the common plough, when the sole becomes convex, is made to go very unsteadily, and often requires the utmost attention and exertions of the ploughman to direct it. What is stated above, however, can only apply to the common plough when out of order by the sole becoming convex.

2635. Placing the wheel. In order to understand in what manner the wheel ought to be placed so as to reduce the friction, it may be necessary to remark that one of the first properties of a plough is to be constructed in such a manner as to swim fair on the sole. This depends principally on the form of the sole, and position or inclination of the point of the sock, together with the point of draught at the end of the beam (a). If these are properly adjusted, the pressure or friction of the sole will be uniform from the point of the share (b) to the back end of the heel (d); or, in other words, the friction will be balanced between these two points by means of the beam (a) acting as a lever, the heel (d) being the fulcrum, and a point over the share (c) the centre of gravity.

2636. The centre of gravity or of resistance will be extended nearer to the point of the share (b), in proportion as the soil has acquired a greater degree of cohesion; as in old pasture ground, or strong clays. But, wherever the point of resistance meets, it is evident that the point of draught at the end of the beam must be placed so as to balance the friction of the sole between its extreme points (b and a). Viewing the machine, therefore (with regard to the friction of the sole), merely as a sledge carrying a cor.siderable weight, by which it is pressed equally to the bottom of the furrow at the extreme points (b and d), it is clear that, by substituting a wheel at the one point (d), the one half of the friction of the sole will be thrown on the wheel. The draught is reduced by the wheel from forty to sixty. six pounds, or from one seventh to one fifth (two hundred and eighty pounds being the power of one horse.)

2637. Wilkie's improved friction-wheel plough for two horses (fig. 312.) was invented by the late Mr. Wilkie in 1825, and is manufactured by his son at Uddingston, near Glasgow. We consider this as by far the most perfect implement of the plough kind that has hitherto been produced. The wheel (a) is placed so as to incline from the

312

perpendicular, at an angle of about 30 degrees; and, following in the angle of the furrow cut by the coulter and share, it ensures a greater degree of steadiness in the motion of the plough than when rolling only on the bottom of the furrow.

The sock or share is of cast-iron, which is a great saving both in first cost and repairs; costing only one shilling, and ploughing at an average upwards of ten acres. Only the coulter requires to be taken to the smithy, the share being renewed by the ploughman at pleasure. The wheel, which is of cast-iron, will last many years. The draught of this plough has been proved at a public ploughing match, in 1829, to be fully 30 per cent less than that of the common scoring plough of the most improved form. The price is also lower than that of any iron plough now in use. Mr. W. has lately made some of these ploughs with a piece of mechanism attached to the wheel, by the revolution of which, the quantity of ground passed over by the plough may be indicated. (Gard. Mag. vol. v.)

2638. The paring wheel plough is of various forms, though it is an implement seldom required. It is used for paring the surface of old grass lands, or leys on clay

313

has a wheel (a) which cuts the turf, instead of a coulter; a broad flat share which raises it, with a sharp fin or turned-up part at the extremity (c), which cuts the turf on that side, thus turning it over in slices about a foot broad and

two inches deep. There is a foot (b) from the forepart of the beam, which serves to prevent the share from going too deep.

2639. Clarke's draining plough (fig. 314.) was found to answer well in

meadow ground near Belford in Northumberland, but could not be drawn in stiff clay

314

with the force of eight horses.

2640. Gray's draining plough (fig. 315.) seems one of the best. The beam is strongly fortified with iron, and is always kept at a proper distance from the surface of the ground, and also the

depth of the drain regulated by two wheels (a a) which turn on an iron axle, and roll upon the surface on

each side of the drain. The middle coulter is made to cut perpendicularly; consequently, the side coulters will cut the two sides of the drain at an equal slope. When this machine is at work, the earth of the drain is cut in the middle by the foremost coulter, and on each side by the other two coulters. Then the sharp point of the share will cut up that earth from its bed, and, as the machine advances, it must ascend on the surface of

315

I

the inclined plane; at the same time, the fore-ends of the mould-boards, following in the track of the middle coulter, will divide the slice of earth, as it rises, into two equal parts, turning these parts gradually to each side; and, as the back-ends of the mould-boards extend farther than the breadth of the drain above, the portion of earth so raised will be placed upon the firm ground, leaving the drain quite open. The frame into which the axle is fixed may easily be either raised up or depressed, as the drain is to be cut deep or shallow; and the two outside coulters can easily be placed more or less oblique, so as to cut the sides of the drain at a greater or less slope, as may be found necessary. (Gray's Implements, &c. 4to.)

2641. Morton's draining plough (fig. 316.) has three coulters (a a b), two mouldboards (c c), and one share (d). The mould-boards have an inclined plane, formed upon

316

I

each (e e), which rises from the share backwards to such a height above the level of the sole as the drain is required to be made deep. The middle coulter separates the soil to be lifted into two parts, and each part is raised to the surface by the inclined planes on the mould-boards. The usual dimensions of the drain so formed are 10 or 12 inches deep, 8 or 9 inches wide at bottom, and 14 or 15 inches wide at top; but the construction may be adapted to a smaller or a larger drain, or for cleaning out drains already made.

317

2642. The gutter plough (fig. 317.) is made use of for forming gutter drains in grass lands, where the soil is of a retentive nature. The power of six horses is required in drawing it for the first time; but four horses are found sufficient for opening the old gutters.

2643. The mole plough (fig. 318.) was invented by Adam Scott, and improved by Lumbert of Gloucester

shire. It is said to be an implement which, in ductile soils and situations, as in pleasurete of

grounds, and where much regard is had to the surface-appearance of the land, may be of considerable benefit in forming temporary drains. It makes a drain without opening the surface any more than merely for the passage of a thin coulter, the mark

Young, and other members of the by which it is worked by the labour of four men. Board of Agriculture, expressed themselves greatly enamoured of this plan; but it is obviously too complicate and expensive for general use.

2645. A subsequent improvement, by Lumbert, consisted in the addition of a gin-wheel and lever, by which the machine was worked by one horse walking round it, as in a common horse-mill; and this last form has again been improved by the late mechanist, Weir, of Oxford-street, London, by the addition of a vertical cylinder, which winds up Weir has also simplified and the chain without any attention from the driver. strengthened this machine in other respects; so that his modification of it (fig. 320.) is,

92 93 105 lbbim sdT

at present, by far the best. of Still we think it an implement that very seldom can be profitably used: that this may be the case, the surface of the field

Dd

must have a natural drainage, by lying in one even slope or slopes; it must be in pasture; But even where and the soil must be of uniform consistency, and free from stones.

these favourable circumstances combine, we think two swing ploughs, with finless shares, following in the same track, would effect the same object sufficiently well for all agricultural purposes; and for drains in ornamental grounds, no machine will ever equal manual labour.

2646. The Duke of Bridgewater's draining plough (fig. 321.) is used for making open drains of a small size (c), regular shape, and from five to nine inches deep. The

321

ה

share (a) has a coulter (b) fixed to it, projecting upwards, to cut one side of the drain, and another coulter (d) fixed to the beam and also to the share at its lowest end. The turf which is thus cut out passes between the coulter (d) and the mould-board (e), and is thus lifted clearly out of the trench. The depth of the drain is regulated by the wheels at the fore end of the beam (ƒ). This plough is drawn by four or six horses.

2647. Various draining ploughs have been invented and tried by Arbuthnot, Makie, M'Dougal, Green, Pearson, and others. Pearson's will be afterwards figured and described. 2648. The pressing plough is properly a roller, and will be found noticed among

machines of that class.

2649. The only essential plough to be selected from these three sections is the improved Scotch swing plough, with or without one or two wheels, according to circumstances; and with the mould-board, share, and coulter, set to suit different soils, as flinty, chalky, &c.; or soils in different states of culture, as old turf, heath, steep banks, ley, &c. SUBSECT. 3. Tillage Implements, known as Scarifiers, Scufflers, Cultivators, and Grubbers.

2650. The use of pronged implements, as substitutes for the plough, is of comparatively recent date. They differ from the plough in stirring the soil without reversing its surface or altering its form, unless, indeed, they in some cases tend to even or level inequalities; they act both as the plough and harrow at the same time, and on suitable soils, and at proper seasons, much more labour is effected with less expense of men and cattle. Wherever, therefore, lands require to be stirred for any purpose except that of reversing the surface, or laying them into beds or ridges, recourse may be had to pronged tillage implements, such as we are about to describe.

2651. In estimating the value of pronged tillage implements, General Beatson (New System of Cultivation, 1820) applies the principle of lessening power and employing time. He says, if we apply the principle of petty operations to any stiff land, by taking that depth of furrow which can easily be ploughed with two horses, and repeat the operation (or plough the land a second time), we shall arrive at the end proposed, that is, the same depth of ploughing, with absolutely less exertion of animal strength than if we were to plough the same depth with four horses at one operation.

2652 This may be illustrated by supposing the resistances to the plough to be in proportion to the squares of the depth of the land. If so, and we are to plough at once with four horses, six inches deep, the resistance at that depth would be 6 x 6 = 36: but if with the same four horses, using two at a time, we plough the same depth of six inches at two operations, taking only three inches at each, then the square of the first depth is 9, and the square of the second, 9; making 18 for the total resistance, or the power expended by the two horses, in ploughing six inches deep, at two operations.

2653. A farther illustration may be made by supposing the same four horses, which had ploughed at once six inches deep, and had overcome the resistance of 6 x 6 = 36, applied, separately, to four light ploughs, or other implements, and to plough only 13 inch deep at a time, and to go over the same land four times. In this case the sum of all the resistances to be overcome, or the animal force expended, in these repeated ploughings, would be no more than 9 instead of 36; because the square of 14=24, which, multiplied by the four ploughings, gives 9, or only one fourth of the power expended in ploughing at once six inches deep. Hence it appears, that in ploughing six inches deep, with four horses, each horse exerts a force = 9; whereas in taking only 1 inch deep, the force he exerts is not more than 24.

2654. Farther, supposing that a horse exerts, in drawing a plough, a force of 160 pounds, it is evident, if four horses are ploughing six inches deep, the total force exerted will be 640 pounds, or 160 pounds by each; but if they be required to plough one inch and a half deep at a time, then the total force expended by the four horses will be only 160 pounds, or 40 pounds by each horse.

2655. Application. This leads General B. to the principle on which his small scarifiers are constructed. "They have," he says, "four hoe-tines in the hind bar, and I will suppose that there are four harrowtines (instead of three) in the front bar, so that each scarifier may be considered as four small ploughs, with four shares and four coulters. If we suppose one horse attached to this implement, and that the force he exerts is 160 pounds, it is obvious that in scarifying to the depth of one inch and a half, he will exert these 160 pounds upon the four pairs of tines, or a force of 40 pounds upon each pair. But, in fact, the force required to draw the scarifier will be considerably less than to draw any form of plough, because the hoe, or share-tines, being much thinner and sharper than a ploughshare and mould-board, will of course meet with much less resistance in stirring the soil." General B. goes on to relate some experiments by which he considers he has " clearly proved that the least expensive method of preparing the land for wheat, after tares, beans, peas, or clover, is simply by using the scarifiers." This we conceive is carrying