440 
obtained ® are invariably much higher than those recorded in the factory, 
where much loss of fiber due to the practical, time-saving methods in 
vogue, is inevitable. Furthermore, many raw materials—abaca waste, 
for instance—are of such a nature as to render the taking of a small, 
representative sample practically impossible. 
The method adopted in the laboratory for determining the percentage 
of cellulose or paper pulp is that used on a larger scale in the factory— 
i. e., severe alkaline digestion at elevated temperatures. It is also true 
that the ease with which the cellulose may be obtained can only properly 
be established by direct experimentation under factory conditions. ‘To 
meet these, we had constructed a model digester of sufficient capacity to 
accommodate several pounds of material and so arranged that it could be 
converted for use with alkali or sulphite liquors, with the necessary steam 
and temperature gauges for carrying out digestions at elevated pressures. 
Proceeding with the chemical examination of a given fibrous substance, 
there are other questions to be determined before the value of a raw ma- 
terial as a source of paper stock is fully expressed. Besides knowing the 
proportion of paper cellulose contained in the material to be considered 
and the ease with which it may be isolated, it is necessary to form some 
idea of its chemical nature—i. e., its general composition and behavior 
with hydrolytic and oxidizing agents—for on such knowledge our ideas 
of the purity and stability of the manufactured product are based. 
PHILIPPINE FIBERS. 
In looking over the field for suitable material for purposes of study, 
our attention was first directed to abacé, or Manila hemp, as it sometimes 
is termed. This plant is a species of wild banana of which there are 
several indigenous to, or introduced into, the Philippine Islands, and, 
as is well known, so-called Manila paper has long been made from worn- 
out ropes of this fiber. Its superior quality for the manufacture of 
special kinds of paper where strength is the desideratum is well demon- 
strated. 
According to the Twelfth Report of the United States Census, Amer- 
ican paper manufacturers purchased approximately 100,000 tons of so- 
called Manila stock for use in their mills; the approximate cost was 
$2,500,000, or $25 per ton. This stock was made up of old, worn-out 
rope, gunny sacks, waste thread, and binder twine, and it includes jute 
® Laboratory method. Paper maker's method. 
(Yield of dry cellulose on (Yield of air-dry pulp on air- 
dry raw material.) dry raw material.) 
Per cent, Per cent. 
Esparto 50-55 438-47 
Straw 50-55 33-37 
Wood 50-50 i 35-43 
Cross and Bevan: Cellulose, 284. 
