Hemp Hurds as Paper-Making Material | Page 2

per cent of
their air-dry weight.
The stalks are sometimes set up in shocks to cure before retting, and
after retting they are set up in shocks to dry. Each time the stalks are
handled they are chucked down on the ground to keep the butts even. In
these operations sand and clay are often driven up into the hollow at the
base of the stalks, and this dirt, which often clings tenaciously, may
constitute all objectionable feature in the use of hemp hurds for paper
stock.
In Italy and in most localities in Russia and Austria-Hungary where
hemp is extensively cultivated, it is retted in water, but water retting
has never been practiced in the United States except to a limited extent
before the middle of the last century. Hurds from water-retted hemp are
cleaner and softer than those from dew-retted hemp.
The fiber is sometimes broken from dry hemp stalks without retting.
The hurds thus produced contain a small percentage of soluble gums,
chiefly of the pectose series. Comparatively little hemp is prepared in
this manner in America.
Process retting by means of weak solutions of chemicals or oils in hot
water is practiced to a limited extent. The hurds from these processes
may contain traces of the chemicals or oils and also soluble gums in
greater degree than those of the dew-retted or water-retted hemp.

=PROPORTION OF HURDS TO FIBER AND YIELD PER ACRE.=
[Illustration: FIG. 1.--Hemp-breaking machine. The stalks are fed
sidewise in a continuous layer 2 to 3 inches thick, turning out about
4,000 pounds of clean fiber per day and five times as much hurds.]
The yield of hemp fiber varies from 400 to 2,500 pounds per acre,
averaging 1,000 pounds under favorable conditions. The weight of
hurds is about five times that of the fiber, or somewhat greater from
hemp grown on peaty soils. A yield of 2-1/2 tons of hurds per acre may
be taken as a fair average.
=HURDS AVAILABLE FROM MACHINE-BROKEN HEMP.=
Hemp hurds are available only from hemp which is broken by
machines, when the hurds may be collected in quantity in one place
(figs. 1 and 2). Most of the hemp in Kentucky is still broken by hand
brakes. These small brakes are moved from shock to shock, so that the
hurds are scattered all over the field in small piles of less than 50
pounds each, and it is the common practice to set fire to them as soon
as the brake is moved. It would be difficult to collect them at a cost
which would permit their use for paper stock.
Where machine brakes are used, the hemp stalks are brought to the
machine as grain is brought to a thrashing machine, and the hurds
accumulate in large piles, being blown from the machine by wind
stackers.
Machine brakes are used in Wisconsin, Indiana, Ohio, and California,
but to only a limited extent in Kentucky. Five different kinds of
machine brakes are now in actual use in this country, and still others
are used in Europe. All of the best hemp in Italy, commanding the
highest market price paid for any hemp, is broken by machines. The
better machine brakes now in use in this country prepare the fiber better
and much more rapidly than the hand brakes, and they will undoubtedly
be used in all localities where hemp raising is introduced as a new
industry. They may also be used in Kentucky when their cost is
reduced to more reasonable rates, so that they may compete with the

hand brake. Hemp-breaking machines are being improved and their use
is increasing. The hemp-growing industry can increase in this country
only as machine brakes are developed to prepare the fiber. A profitable
use for the hurds will add an incentive to the use of the machine brake.
[Illustration: FIG. 2.--Machine brake and hemp hurds. Hemp hurds
from machine brakes quickly accumulate in large piles.]
=PRESENT USES OF HEMP HURDS.=
Hemp hurds are used to a limited extent for barnyard litter and stable
bedding, as a substitute for sawdust in packing ice, and, in rare
instances, for fuel. They are not regarded as having a commercial value
for any of these uses, though they are doubtless worth at least $1 per
ton on the farm when used for stable bedding. They are a waste product,
without value for other purposes which might compete with their use
for paper stock.
=PRESENT SUPPLIES OF HURDS AVAILABLE.=
During the last season, 1915, about 1,500 acres of hemp have been
harvested outside of Kentucky and in regions where machine brakes are
used. Estimating the yield of hurds at 2-1/2 tons per acre, this should
give a total quantity of about 3,750 tons. Large quantities of hemp from
the crop of 1914, which are still