Plough, an instrument for breaking up, turning over, mixing, or loosening the soil, drawn by animal or steam power. The plough of the ancient Egyptians was of wood, a single crooked stick serving for the tail, which, extending below the place where the horizontal beam was secured to it, formed the point or share. This was stiffened by a rope which passed up from it to the beam, and the handle was divided so as to present a hold for each hand of the ploughman. (See fig. 1.) Wilkinson thinks it probable that the point was shod with a metal sock, either of bronze or iron. In the Old Testament metallic ploughshares are alluded to more than seven centuries B. C: " They shall beat their swords into ploughshares." (Isa. ii. 4; Micah iv. 3.) In the time of Hesiod two sorts of ploughs were in use among the Greeks. One was formed of a limb of a tree having two opposite branches diverging like the arms of an anchor from its shank.
The main stem served as the beam or pole by which the plough was drawn; one arm, sometimes shod with iron or bronze, entered the ground, and by the other the implement was pressed into the ground and guided. The other kind was constructed of three sticks secured together by nails; one was the beam, which at its lower end was joined to the nearly horizontal share, and from this proceeded the tail or handle. Figs. 2 and 3 are wheel ploughs from Caylus's collection of Greek antiquities, showing forms used in the 3d century B. 0. Fig. 4 shows a Greek plough used in Sicily before Syracuse was taken by Marcellus, 212 B. 0. Fig. 5 shows a modern Assyrian plough. Fig. 6 is the modern plough of Castile, and fig. 7 that which is now used in Sicily. Among the aborigines of North and South America the plough appears to have been almost entirely unknown. The Peruvians, who were the most skilled in agriculture, employed, as described by Prescott, a rude substitute constructed of a strong, sharp-pointed stake, traversed by a horizontal piece 10 or 12 in. from the point, on which the ploughman might set his foot and force it into the ground.
Six or eight strong men were attached by ropes to the stake and dragged it forcibly along, accompanied by women, who followed to break up the sods with their rakes. - The modern plough originated in the Netherlands, whence England obtained most of her knowledge of;field and kitchen gardening. In the early part of the 18th century many ploughs were imported from Holland. The mouldboards and shares of these ploughs were made of wrought iron or steel, but about 1784 James Small of Berwickshire, Scotland, who wrote a treatise on ploughs, made cast-iron mouldboards and wrought-iron shares; and in 1785 he made cast-iron shares. The American plough during the colonial period was of wood covered with sheet iron, the share being wrought. In 1797 a cast-iron plough was patented by Charles Newbold of New Jersey. Thomas Jefferson about the same time investigated the subject, and formed a theory of the proper shape of the mouldboard, which he treated as consisting of a lifting and an upsetting wedge, with an easy connecting curve. Daniel Peacock, in 1804 or 1807, patented a plough having the mouldboard and landside of cast iron and separate, while the share was of wrought iron edged with steel.
Jethro Wood of Scipio, N. Y., patented improvements in 1819, and for a long time was known for making the best ploughs in market. - In the most approved ploughs now in use, of the breaking-up class, the mould-board is made of plate steel, its external surface concave and corresponding in its curve to the segment of a cylinder, of which, however, it would comprise but a small portion. The breaking-up ploughs are the most important of the several sorts of this implement. The depth to which they penetrate is regulated, as in other ploughs, by the contrivance at the end of the beam called the clevis, to which the draught chain is attached. This is a sort of rack or elongated iron staple, into which the chain is hooked, high up for deep ploughing, and lower down if the ploughing is to be shallow. The greatest depth reached by those of the largest size is about 18 in., and the width of the furrow about 24 in. As a breaking-up plough is run through soil of some tenacity, as prairie or grass lands, the furrow is regularly laid flat over to one side; and as the plough comes round again another adjoining slice is laid against the former one; and so the work goes on till the whole field is covered with the long overturned slices of earth and sod laid flat or slightly lapped at different angles on each other, as the nature of the soil may require; in stiff clayey soils an angle of about 45° is best.
A wheel is often placed at the end of the beam, which runs upon the surface of the soil, and from which the beam may be raised or lowered. A wheel sward plough of good construction is represented in fig. 8. Sidehill ploughs are breaking-up ploughs with the mouldboard so arranged that, after running through the furrow along the side of a hill, it may be instantly shifted round and secured on the other side of the beam. By this contrivance the plough may pass directly back and turn the next furrow down the slope of the hill against the one which preceded it. Most of the modified forms of mouldboards, ploughshares, etc, are introduced with the special object of reducing the friction to a minimum and thereby lessening the amount of horse power. The beams and handles of ploughs are, for the sake of lightness, generally preferred of wood, though some are still made in the manner much in vogue a few years ago, especially in England, entirely of iron. Gang ploughs, constructed by placing from two to four or even more ploughs on a common frame, one diagonally behind another so that the furrows are made to overlap each other, are often used upon prairie or level land, drawn by several yoke of oxen or spans of horses, or by steam power.
By reducing the size of the plough bodies and increasing their number, the implement becomes the cultivator, which is made to cut at once a number of parallel shallow furrows. For merely stirring and loosening the soil to produce the effect of hoeing, ploughs of great simplicity are in use, which are not very different from some of the ploughs of the ancient Greeks and Egyptians. One class of these, known as bull-tongue ploughs, are largely used in the southern cotton and corn fields. The share is pod-shaped, and is driven through the ground with the convex surface forward. Subsoil ploughs are used to run in the furrow behind the turn-over plough to break up the subsoil to any desired depth, but without turning it up. They have a beam and handles like an ordinary plough, but no mouldboard or share, having in place of them a strong flat standard of sufficient height, armed with a point. They are not required in very porous soils. - The first steam plough, or plough moved by steam power, which was practically or successfully worked in the field, was patented by Mr. Heathcote, M. P., of England, in 1832. A patent had been obtained by Major Pratt in 1810, whose plan employed two steam engines, one on each headland, drawing a plough between them by means of an endless rope.
It also embraced the modern plan in steam ploughs of having two sets of them placed back to back, one being elevated and out of the ground when going in one direction, and vice versa. In 1769 also a specification for a patent was made by Francis Moore for a machine or engine to plough, or do any other branch of husbandry, without the aid of horses. Mr. Heath cote's machine was intended for breaking up and draining swampy land, and consisted of a locomotive steam engine placed upon a headland and opposite a carriage on another headland, by which means an endless chain carried the plough backward and forward. In 1836 this plough, it is said, was worked with tolerable success at Red Moss in Lancashire; but at a trial near Dumfries in 1837 its performance did not warrant the judges in awarding the prize of .£500 which had been offered for a successful steam plough. The apparatus was cumbersome and expensive; the engine was of 25-horse power, and the work required the employment of ten men and boys.
After this improvements were made upon the plan of Major Pratt by Alexander McRae and also by Mr. Tulloch in 1846, and again by Mr. McRae in 1849. In 1854 Mr. John Fowler exhibited a patent steam draining apparatus, in which a balance gang plough, the construction of which is shown in fig. 9, was moved back and forth by means of an endless rope attached to a steam engine placed at one headland, and passed around a drum at another. At the Newcastle show of the royal agricultural society in 1864, Mr. Fowler introduced two engines, each of seven-horse power, working upon opposite headlands, in which the performance was satisfactory. Howard's system of steam ploughing employs a rope whose line of draught may be changed by fixed pulleys at the corners of the field, so that the position of the engine need not be changed so often. Considerable numbers of both these ploughs are made in England and sent to the East and West Indies and to Egypt, and there are said to be more than 1,000 steam ploughs now in use in England. Recently locomotive engines called traction engines have been brought into use as a motive power for ploughs in England, and some of them have been imported into the United States. Messrs. Aveling and Porter of Rochester, England, have devised a traction engine for ploughing, which has been used upon the estate of A. T. Stewart at Garden City, Long Island. The English gang, however, which consisted of four ploughs, each intended to turn a furrow 12 in. wide, was not found adapted to the work required of it at that place, and a new one designed by Mr. W. R. Hinsdale was substituted, and is now in use, which turns three furrows, each 14 in. wide, in a very satisfactory manner.
The principal features of the new. gang are the reduction of the supporting wheels from four to two, one at either side and end, and placing the points of the shares on a line connecting them. By this means inequalities in the surface of the soil produce less interference, and a more uniform depth of furrow is secured. The raising of the ploughs so as to clear the ground during transportation and turning at the headlands is effected by the levers h and l, fig. 11. The ploughman upon the seat k, by pulling the lever h forward, brings the clamp i upon the rim of the wheel b, and elevates the rear end of the frame to which the lower end of the lever is attached. The point of attachment is the axle of the wheel g. This being turned makes traction upon the wire rope/, which is fastened to its periphery, passing over the pulley p. This traction causes the lever I to raise the standard (supplied with a double joint) of the wheel a from an inclined to a vertical position, thereby elevating the forward end of the frame simultaneously and to a corresponding height with the rear end. The beam of the plough is moved to the right or left by means of a rack and pinion at d, controlled by the wheel c in the hands of the ploughman.
The mouldboards of these ploughs were designed by Mr. S. A. Knox of Worcester, Mass., and are remarkable for their easy draught. The engine with the plough in position, and an enlarged view of the plough, are shown in figs. 10 and 11. The engine has only one steam cylinder, which might be thought insufficient where so great a constant strain is required as in hauling a plough; but the momentum of the rapidly rotating fly wheel supplies sufficient power at the dead points, the piston with a pressure of 120 lbs. per square inch being capable of making 150 strokes per minute. The engine is also used to haul trains of wagons, to drive threshing machines, mills, pumps, and saws, and as a general motive power.