PLOVER. 123 PLOW. closely resembling the ringed plover, of which the semipalmated or "ring-neek' {JEyialitis semi- jiulmata) is the American analogue. The largest and best known is the kildeer (q.v. ). The pip- ing plover (Jilgialitis meloda) is found along the Atlantic coast, and is notable for the musical quality of its notes. The snowy plover {/Egiali- tis nirosa) is a handsome species found in the southwestern United States. All of the ring- plovers lay their three or four eggs in a depres- sion in the ground ; the eggs vary in color from creamy-white to olive-drab, heavily marked with blackish-brown. In the Western United States occurs the mountain plover (q.v.), which difl'ers from the others in the absence of any black belt or markings on the neutral surface. The 'beetle- head' or black-bellied plover iChtinidi-ius sqiiatu- roln) is a nearly cosmopolitan form, recognizable in any plumage by the small hind toe and the rounded scales on the front of the tarsus. It is nearly a foot long, and in full plumage is a very handsome bird, black and wliite contrasting in its plumage to make it notable. It breeds in the Arctic regions and winters in the tropics. The bird known to American sportsmen as the 'up- land plover' is not a plover at all, but a sand- piper (Bartramia Inngicaiida) . Several remarkable birds of this group belong in South America, Africa, and Australasia. One of these is the EgA'ptian 'spur-winged" plover (q.v.) ; see also Crocodii.e-Bird.) Another is the strange 'crook-billed plover' of Xew Zealand. (See Wrtbill. ) Closely allied to them are the European and Asiatic 'lapwings.' and the South American 'teru-teru' (q.v.) of the widespread ■genus Vanellus. Consult: Dresser, Biids of Eu- rope (London. 1881) ; Seebohm, Birdx of Ania (ib., 1888); Buller, Bi>f7.9 of Xew Zealand (2d ed., ib., 1888); Shelley, Birds of Egypt (ib., 1872) : Sharpe and Hudson. Argentine Ornithol- Ofi!/ (ib., 1888) ; Walsingham, "Shooting." in Badminton Library (ib.. 1889) ; Elliot. Shore Birds of Xorth America (Xew York. 180.5) : Lef- fingwell. Shooting on Upland, Marsh, and Streiriii (Chicago. 1890). See Plate of Egks of Water AND Game Birds; and Plate of Plovers. PLOW, PLOWING (AS. pJoh. OHG. pftiioh. GV>r. Pftng, plow; connected with Longobardic plornm. and possibly with Gk. -yXoixI", gJoehin. projecting point). In all countries where agri- culture is in an advanced state, the first agricul- tiral operation in order and importance is the breaking up of the soil by inverting the upper stratum of earth upon which the plants grow. Such an operation also buries and destroys weeds ; leaves the surface clean, unencumbered, and in a condition favorable for weathering; in- creases the storage capacity of the soil for water; but also assists percolation and thus aids in dry- ing and warming the soil. To the unobservant, the plow seems a simple and even primitive tool; yet it is the product of slow evolution and much mechanical skill. The plow in primitive form probably antedates his- tory. The Old Testament mentions plows shod with iron or bronze, but except in Western Eu- rope and America little progress has been made in improving the implement since the time of Herodotus. One of the earliest types of plows is shown in Fig. 1 ; a type of the ordinary modern plow in its simple form in Fig. 2. As will be seen, the modern plow consists of several parts — - Vol. XVI.— 9. a beaui, by which the plow is drawn, which may be of wood or metal; two handles, usually wood, for guiding. To the end of the beam a clevis or bridle is attached for convenience in hitching the team and regulating the depth and width of furrow, and near the outer end a small adjust- able wheel (frequently omitted) for assisting in steadying the plow and regulating the depth of the furrow. Behind this is a coulter for cut- ting the furrow slice at the side. This coulter takes various forms — a miniature plow or joint- er, a stout iron knife, or a revolving disk with sharp edge. Back of the coulter is the plow proper, consisting of a strong cast-iron frame (standard or sheath) firmly fastened to the beam and braced bv the handles in rear. To this frame Fig. 1. PRIMITIVE PLOW. is attached a pointed share for cutting the fur- row slice at the bottom, a mold-board for turning the furrow slice, and the land-side opposite the mold-board, which presses against the side of the furrows and helps to steady the plow. The first patent for a plow is said to have been obtained by .Joseph Foljamb in 17.30. and Jethro Tull about this time invented a plow de- signed especially to pulverize the soil thoroughly, an idea embodied in modern plows of the best Fig. 2, AMERICAS PLOW. type. Figure 3 shows the Rotherham plow used in Holland at the beginning of the eighteenth century, and afterwards introduced into England. In attempts to improve the plow the mold-board, which raises and turns the furrow slice and which appeared in the plows of the Netherlands during the seventeenth century, has probably received more attention than any other single part. Thomas .Jefferson, who published his views in 1798. and .James Small in 1802, were among the first to attempt to establish the proper lines of the mold-board upon a mathematical basis. Fig. 3. EARLY DUTCH PLOW. As determined by the shape of the mold-board, ordinary plows are of two main types, (1) 'sod- plows' with long sloping mohl-board which turn a narrow, flat furrow without pulver- izing the furrow slice, but which bury vegetation, manure, etc., effectually; and (2) the 'stubble
