[Illustration: THE MODERN FOURDRINIER MACHINE--PAGE 73] ♦The washers or Hollanders♦ It is here that the process of cleaning begins in earnest; and as the mass of rags is tumbled about in its scalding bath of steam-heated lime-water, or “milk of lime,” the coloring and glutinous matters, as well as all other impurities, are loosened from the fibers, which are in the end so cleansed and purified as to come forth unstained and of virgin purity. Having been sufficiently boiled and digested, the mushy material, still looking dark and forbidding, is emptied onto the floor below or into receptacles placed directly beneath the boilers, where the color and dirt are allowed to drain off. The mass is then conveyed to the “washers,” great tub-like receptacles, which are shown among the illustrations, and which are known as “Hollanders,” from the fact that these rag engines were invented in Holland, about the year 1750 A. D. They are oval-shaped tubs, about twenty feet long, nine feet wide, and three feet high, varying somewhat according to the conditions. Each tub is divided for two-thirds of its length by an upright partition, or “mid-feather,” as it is called, which makes a narrow course around the vat. On one side of the partition the tub is raised in a half-circle, close to which revolves an iron roll about three or four feet in diameter, and covered with knives; in the bottom of the tub, and directly under the revolving roll, is another set of knives called a “bed-plate,” which is stationary, and against which the roll can be lowered. But not to anticipate. When the emptyings from the boiler have been thrown into the “washer” a continuous stream of water is turned in at one end, the knife-roll having been adjusted so as to open up the rags as they are set in motion. These then begin a lively chase around the edge of the vat, through the racecourse formed by the “mid-feather,” and under the rag-opening knives, where the water is given a chance to wash out all impurities; then on up the incline over the “back fall,” so-called from the elevation in the tub. A cylinder of wire cloth, partly immersed in the moving mass, holds back the now rapidly whitening fibers, while the dirty water escapes into buckets inside the wire cloth drum, and is discharged into and through an escape-spout. The heavy particles of dirt settle into what is termed a “sand-trap” at the bottom of the tub. ♦Bleaching material♦