Forest Service, U. S Dept. of Agriculture Mechanical Pulp. 



PLATE VIII. 



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FIG. 1. 152 R. P. M. (RUN No. 19.) 



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FIG. 2.-205 R. P. M. (RUN No. 20-1.) 

 COMPARISON OF JACK PINE PULPS GROUND AT DIFFERENT SPEEDS. 



