GROUND-WOOD PULP. 



27 



yields a shorter fibered pulp, with a color inferior to that obtained 

 from the green material. Green wood likewise requires less power 

 to grind it, although the difference in the power consumption per ton 

 between that obtained from green and seasoned wood is very small. 

 The weight per cubic foot of wood is a most important factor, 

 since upon it depends almost entirely the yield per cord. This is 

 best shown in figure 20, where the dry weights of a number of dif- 

 ferent species are plotted against the yield of pulp per 100 cubic 

 feet of solid rossed wood. It has been found that the yield is almost 

 directly proportional to the bone-dry weight per cubic foot. 



40 60 80 100 120 250 300 350 400 450 

 HORSEPOWER PER TON [BONE DRY] HORSEPOWER TO GRINDER 



2 3 4 5 6 



TONS IN 24 HOURS [BONE DRY] 



Fig. 17.— Relation of power consumption and production to steaming pressure— horsepower to grinder 

 constant. (Spruce runs 233 to 242, inclusive.) 



The following is a list of woods corresponding to the numbers shown 

 on the curves in figure 20: 



No. 1. Balsam fir. 



2. Red fir. 



3. White fir. 



4. Alpine fir. 



5. Amabilis fir. 



6. Lowland fir. 



7. Noble fir. 



8. Eastern hemlock. 



9. Western hemlock. 



10. Tamarack. 



11. Western larch. 



12. Montana lodgepole pine. 



13. California lodgepole pine. 



i Commonly called 



No. 14. Western yellow pine. 



15. Jack pine. 



16. Loblolly pine (fall cut). 



17. Loblolly pine (spring cut). 



18. White pine. 



19. Engelmann spruce (Montana). 



20. Engelmann spruce (Colorado). 



21. Sitka spruce. 



22. White spruce. 



23. White birch. 



24. Aspen. 1 



25. Black 'gum. 



'popple" in Wisconsin. 



