Hemp Hurds as Paper-Making Material | Page 5

the whole material would probably be somewhat
higher than that of the hurds, because either all or part of the cost of
harvesting and the total cost of breaking would have to be borne by the
paper maker. Moreover, the quality of this material would be so very
irregular and the supply so uncertain that it probably would not appeal
to the paper manufacturer.
Without doubt, hemp will continue to be one of the staple agricultural
crops of the United States. The wholesale destruction of the supply by
fire, as frequently happens in the case of wood, is precluded by the very
nature of the hemp-raising industry. Since only one year's growth can
be harvested annually the supply is not endangered by the pernicious
practice of overcropping, which has contributed so much to the present
high and increasing cost of pulp wood. The permanency of the supply
of hemp hurds thus seems assured.
The favorable location geographically of the hemp regions in relation
to the pulp and paper industry is a factor of considerable importance.
The Kentucky region is not at present in a position to supply hurds, as
machine methods have not been adopted there to any appreciable
degree. The Ohio and Indiana region, which at present has the greatest
annual tonnage, with the prospect of an increase, is situated south of the

Wisconsin and Michigan wood-pulp producing region and at a distance
from the eastern wood-pulp producing regions; therefore, it is in a
favorable position to compete in the large Ohio and Indiana markets.
Since, as will be shown, the hurd pulp acts far more like soda poplar
stock than sulphite stock, competition would be strongest from the
eastern mills; in fact, the hurd stock might very possibly meet with
favor as a book-stock furnish in the Michigan and Wisconsin paper
mills, which are within the sulphite fiber-producing region. Because of
its very close proximity to paper mills, this latter possibility applies
with far greater force to the Wisconsin hemp region, where a
considerable extension of the hemp industry is anticipated.
[Illustration: FIG. 3.--A representative sample of hemp hurds, natural
size, showing hemp fiber and pieces of wood tissue.]
=CHARACTER OF THE MATERIAL.=
As received from Pierceton, Ind., the hurds consisted of a mixture of
tangled hemp bast fibers and pieces of broken wood of the hemp stalk.
(Fig. 3.) No reliable data were secured as to the proportion of bast fiber
in the total shipment of 4 tons, although two hand separations of small
representative samples gave results averaging 8 per cent. The chemical
character of the material was such and the quantity was so small that
any appreciable variation of the proportion should not affect materially
the treating processes finally adopted, yet its presence in varying
proportions undoubtedly would modify to some extent the quality of
the resulting paper product. Since the length of the ultimate bast fiber
averages about 22 mm. and the length of the ultimate hemp wood fiber
averages 0.7 mm., it is natural to assume that the bast fiber would tend
to increase the strength of paper produced from the hurds. (Fig. 4.)
[Illustration: FIG. 4.--Fiber derived from the woody portion of the
hurds. ×75. From a microphotograph.]
The broken pieces of wood contained in the hurds varied in length from
mere particles which were somewhat finer than sawdust to pieces about
3-1/2 inches long, exceptional pieces being found which measured 6
inches in length. The majority of the long pieces were between 2 and 3

inches in length. In thickness the pieces ranged from one-eighth of an
inch, in case they were derived from the base of the hemp stalks, to
about one sixty-fourth of an inch in those pieces which were derived
from the top and branches of the stalks. In cross section the pieces often
were found to be a quarter or half of the rounded rectangular woody
shell of the stalk, although there appeared to be no regularity in this
respect.
From the pulp-maker's standpoint the great irregularity in thickness,
length, and mass of the woody pieces militates decidedly against
economy in pulp production. The smaller pieces reduce by chemical
treatment sooner than the larger fragments and are thereby overtreated,
which results in a lower yield of cellulose fiber and a product
composed of undertreated and overtreated fibers, the production and
use of which are not satisfactory or economical. It probably would be
found more satisfactory, therefore, to screen or sort the hurds and treat
the various sizes separately and differently.
Associated with the hurds was a small quantity of chaff and dirt,
composed chiefly of sand, soil, particles of hemp leaves and flowers,
and other extraneous matter. The sand and soil were present because of
the practice of placing the stalks in shocks in the field, the butts of