26 BULLETIN 72, U. S. DEPARTMENT OF AGEICULTUEE. 
that the high gravity of the wood and the resultant high yield of 
pulp per cord give longleaf pine an advantage possessed by few, if 
any, other commercially important woods suitable for pulp making. 
The autoclave tests indicate that there should be a certain com- 
bination of values for the variable cooking conditions which will 
result in the most economical method of operation. However, 
other factors than the variables thus far investigated must be taken 
into consideration in determining what this combination is. For 
example, the proper degree to which a pulp must be cooked will 
depend partly upon the cost of the beater treatment. With cheap 
power for beating, the pulp need not be so severely cooked as when 
the cost of power is high. The best concentrations and proportions 
of chemicals in the digester liquors will likewise depend upon the 
efficiency of the recovery system and the method- of operating it. 
o 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1914 
