WOOD TVW AXD rAPER 45 



in the paper mill. Laps made up in this way contain about 60 per cent of 

 water. 



Drying. 



In the manufacture of dr\- pulp the pulp passes from the screens into a 

 box containing a revolving cylindrical screen and is picked up and carried 

 on a felt the s^ime as in the case of the lap machine. In this case, how- 

 ever, it is carried through a series of three sets of press roUs which press 

 the water out of the sheet of pulp. This sheet i? then carried over a set 

 of about ;o hot cylindrioil dnmis which are arranged ver\- similarly 

 to those of a paper machine. These dnuns are heated by steam and are 

 kept at a temperature of about 150' F. As the dry pulp comes oft the 

 rolls it is wound on a reel at the end of the machine. There are two of 

 these reels and while one is winding up the pulp that on the other is re- 

 wound and run through a set of knives and re-wound in rolls 2 ft. long 

 and weighing about -cc lb. These rolls are then tied, and loaded into the 

 avr for shipment. 



Dry pulp is never made in a mill where the pulp is going directly into 

 paper as it is unnecessarA" to drive off all of this water. Dr\- pulp is m.ide 

 for long shipment and long storage. 



Power. 



Power in a pulp mill is not restricted to am- one t\-pe. In many 

 plai.es water power is used entireK". Steam is also used and electricity is 

 used where it can be manufactured cheaply. 



A I co-ton mill requires about 1500 h.p. to operate it. 



Cost of Productioii. 



The cost of manufacture of pulp \"aries in different mills but a good 

 average before the war would be about ?;5.co a ton. imbleached. The 

 process of bleaching added about Si^.co to this initial cost. 



Spruce and hemlock, in the suromer. are practically alike and sell at 

 the same price, but in winter they \-ar>" greatly, both in quaht\- and sale 

 price. 



At a large pulp miU in Xew York the following costs were determined 

 o\-er a period of several months in 1916: 



