PLOUGH 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 PLOVER 617 FIG. 9. 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 pass- ed around a drum at another. At the New- castle show of the royal agricultural society in 1864, Mr. Fowler introduced two engines, each of seven-horse power, working upon op- posite 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 In- dies 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 sur- face 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 Z, fig. 11. The ploughman upon the seat Jc, by pulling the lever h forward, brings the clamp i upon the rim of the wheel 5, 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 in- clined 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 FIG. 11. 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 Ibs. 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. PLOVER (Fr. pluvier, rainy), the common name of the charadriricB, a large group of wa- ding birds, very generally distributed over the world ; so called because their flocks migrate during the rainy season in autumn. They have a moderately long and slender bill, with cul- men depressed at the base but vaulted at the tip, much as in the pigeons ; sides compressed, and in the groove are placed the nostrils; wings long and pointed ; tail moderate, broad, and generally even; tarsi usually long and
