Page:The American Cyclopædia (1879) Volume XIII.djvu/636

 616 PLOUGH on ploughs, made cast-iron mouldboards and wrought-iron shares ; and in 1785 he made cast-iron shares. The American plough du- ring 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 sepa- rate, while the share was of wrought iron edged with steel. Jethro Wood of Scipio, N. Y., pat- ented 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 sur- face 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 shal- low. 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 re- quire; 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. Side- FIG. 8. hill 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 contri- vance 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, plough- shares, &c., 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 pre- ferred 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 cultiva- tor, 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 cot- ton and corn fields. The share is pod-shaped, and is driven through the ground with the con- vex 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 re- quired 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 loco- motive 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 Eed 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