The steps subsequent to cooking chemical pulps of all kinds are similar. After emptying the digesters, the soft, discolored mass of fibers is washed and bleached. The yield of cellulose fiber is close to fifty per cent of the air-dry weight of the wood. The shives and undigested particles are removed by screening, and the pulp is either run out like ground wood on wet machines, or made up into rolls, or sheets, on a paper-machine. The soda pulp is shipped in rolls and the sulphite in sheets, as this is the most favorable form in which to handle them at the paper-mill. If the pulp is to be used on the premises, it is made up into laps on the wet machine and is not artificially dried. The so-called “air dry” pulp contains about 10% moisture, and pulp containing not over this amount of moisture is billed at its actual weight. [Illustration: CYLINDER MACHINE FOR DRYING PULP, THE BROWN CO. The web of pulp is shown as it passes from the cylinder mold over the couch roll toward the driers.] ESPARTO AND STRAW.--Esparto pulp is made by the soda process from a grass obtained in the circum-Mediterranean countries, and is used most extensively in England and somewhat on the Continent, but freights have been prohibitive for American manufacturers. Straw pulp is similarly made, and while occasionally used on medium grades of writing-papers, its principal use in this country is for strawboard and cheap wrappings. It is expensive to reduce to a clean, bleached pulp on account of its knots, and the large quantities of silicious matter it contains. WASTE PAPERS.--The next largest source of paper-making fibers to wood is the waste paper, such as old books, magazines, newspapers, binders’ waste, paper shavings and miscellaneous waste. This stock is collected by regular packers, sorted, and sold by grade to the mills. The poorest grade consists of a mixture of miscellaneous papers of all colors and description. It is only used in the production of boxboards, sheathing paper, and other coarse varieties, and without undergoing any preliminary treatment it is shoveled right into the beaters. A higher grade consists only of mixed papers, printed or unprinted. Next is a grade containing no ground wood or colored papers, and above this are graded old ledger and writing papers. [Illustration: THE BEATER-ROOM, CRANE & CO. The beater at the far end of the room is equipped with a washing drum. This drum is lowered into the tub during the process of washing.]