Wooden Paper 



buys it. It goes from the rubbish heap in vast quantities back 

 to the paper mill, to be bleached and used over and over again. 



THE MAKING OF SULPHITE 



There is a new process of separating the wood fibres from 

 other organic substance by chemicals. Everything but the 

 tough cellulose is removed, and it makes a strong paper. I 

 visited one of these mills. The chemicals used produce a pulp 

 called in trade "sulphite." 



The Wood. This mill, on the bank of the Delaware, soon 

 consumed all the available wood on the hill slopes of the 

 neighbourhood. Now the supply comes in on cars from regions 

 more remote. Hemlock and spruce are the only kinds used 

 here. They are sound and green and cost at the mill about $6 

 per cord. The sticks average six inches to eight inches in 

 diameter, and are sawed in two-foot lengths. The smaller the 

 sticks, the greater the bulk of clear stock per cord and the less 

 waste in bark. 



The blocks of wood are stored in the basement and go in their 

 turn to the peeling machine, whose knives remove the bark in 

 thin slivers, leaving the blocks white and smooth. The bark is 

 carried into the furnace, for it has considerable fuel value, and 

 must be put out of the way. The blocks next pass to a machine 

 where they are chipped into flakes, much like chips on a woodpile. 

 These are carried to a great cauldron called the "Digester," 

 with capacity of four or five tons of chips. 



The Acid Solution. In the end of the building farthest 

 away from the stored blocks of wood are the raw materials 

 that combine to convert wood into sulphite. In one bin is dry 

 sulphur, or brimstone, shovelled in by the ton. In another is 

 air-slacked lime. Into a large tank of lime water the fumes 

 of burning sulphur are introduced. The acid solution thus 

 produced is the liquor poured over the chips in the digester. 

 Under a pressure of eighty pounds of steam the chips cook for 

 about twelve hours or longer. The judgment of an experienced 

 tester is needed to decide when the cooking is done. 



To scoop out this mass of hot pulp, reeking with strong 

 chemicals, would seem a dangerous as well as diflicult operation. 

 On the contrary, it is very simply done. A tube at the bottom 

 of the digester is nov/ opened. It leads to an empty Receiving 



545 



