wagon, as applied to the transport of merchandise and heavy loads, has many forms. As above stated, the first forms of wheeled vehicles were oxcarts and chariots; the four-wheeled vehicle was much later. One of the Scythian wagons measured zo feet between the low wheels; the axle was like a ship's mast, and the wagon was drawn by twenty-two oxen, eleven abreast. The high-wheeled wagon was derived from the barbarians. The perch or coupling between the fore and hind axles was added in the Middle Ages. The char of the fourteenth cen tury (the state carriage of that period) was but a wagon whose shafts were fastened to the wagon-body and the two axles fastened to the bed—an arrangement which must have made the wagon difficult to turn.
Dumping-wagons.—One of the arrangements for transport and dump ing is the dumping-wagon. In this the bed rims back on rollers by power applied through a winch and ropes. By a reversal of the tackle the bed is replaced. A modification is the coal-chute wagon, in which the body by means of a mechanism actuating levers is so elevated that the coal can be discharged into chutes or troughs, and thus conveyed to the cellar.
hand-truck is an efficient vehicle for removing single packages of considerable weight, and it is an indispensable auxiliary in ware houses, express-offices, etc. In its simplest form, the hand-truck consists of a flat rectangular, tapering frame of oak or other tough timber strongly fastened together by bolts, the main pieces of the frame being converted into curved handles at one end, and connected at the other end with a flat curved bar, which is so bent as to stand at an angle of about 45° with the plant of the frame-work. The frame or bed is mounted on an axle, and heavy wheels of small diameter placed a short distance from the bar-end of the bed; which arrangement gives the leverage necessary for loading weighty packages on the truck. With the handled end of the truck frame in a nearly vertical position, the curved bar is inserted under the lower edge of the parcel—for example, a box—which is then tipped back against the bed, while at the same time the handles are depressed, so that by this means the article is lifted on the truck for conveyance to any desired place.
—The first wheelbarrow, dating from as early as the thirteenth century, differed but slightly from the barrow now commonly employed. The varieties of wheelbarrows are as numerous as are the uses for which they are required, and according to their uses they are named— grading, garden, express, brick, dumping, porterage etc. barrows. In rail
way constrtiction the grading barrow is an efficient machine for removing the excavated earth. It has a small wheel, widely diverging handles, and a scoop-shaped body, so adapted as to dump on either side. The express barrow is a superior form of warehouse or baggage-truck for conveying heavy loads on a floor. The load is balanced on a central pair of wheels, while a wheel at the two ends restrains the oscillation within moderate limits. The Chinese barrow has but one large central wheel placed in the centre of the bed; the entire load rests on this wheel.
Conveyers.—For the horizontal transport of materials there are em ployed other mechanical means, such as conveyers, rope transmission, cranes, etc. The conveyer consists of a conduit in which is a continuous spiral blade around a horizontal axis, the rotation of which causes the screw-like blade to push forward the materials (grain, etc.) from the in itial to the terminal points, similar to the operation of the Archimedean screw (page 327). Rope transmission may either be by a travelling wire rope or by a stationary rope on which the loads (coal, ores, etc.) are sus pended and moved by animal power; for example, the hay-trolley (page 187)—or by electricity. (See Vol. V. page 236.) Cranes and allied mech anisms, which primarily have a vertical movement, are more properly classed with hoisting apparatus, which will be described in the succeeding treatment of transport machines whose action is in a vertical plane and to a limited extent horizontal.
Gins. —Changes of location within a short distance vertically, or, more specifically, within a very narrow sphere of action, are effected by means of gins. These are portable hoisting-machines whose frames are tripods. One of the legs of a gill is movable, to permit of a variation in its angle of inclination, so as to adjust the height of its apex. For raising heavy weights a fall and tackle is employed, but in mining or in hoisting a bucket from a well there are provided a couple of pulley-blocks, one of which is suspended from the apex of the frame, the other being suitably anchored between the two permanent legs. By this arrangement the direction of the draughts of the rope is changed to a horizontal position, thus providing for the attachment of a horse or other motive power for raising the load suspended from the vertical rope. A contrivance similar to the gin is mentioned by Vitruvius.