. 143, and it is also a good
illustration of the extent to which proper tinting will enhance the
general appearance of a paper. The poor appearance of the samples of
previous runs is due largely to lack of proper tinting. Various degrees
of whiteness, however, are demanded by the trade.

=COMPARISON OF THE TESTS AND COMMERCIAL PRACTICE.=

In work of this nature and on this scale it is practically impossible to
arrive at a cost figure which would be susceptible of commercial
interpretation, and in this preliminary publication nothing will be
attempted beyond a comparison of the process used with the hurds with
that process commercially applied to poplar wood. The process last used
with the hurds should not be regarded as final, satisfactory, or most
suitable, as it has been shown that progress was being made up to the
conclusion of the work.

In comparing the method of using hurds with the method of handling
poplar wood, a difference is apparent on the delivery of raw material at
the mill. Ordinarily, poplar is received at the mill in the form of logs
about 4 feet in length, which may be stored in piles in the open. Hurds
very likely would be received baled, and it would seem advisable to
store them under cover for the following reasons: (_a_) Baled hurds
would probably absorb and retain more water during wet weather than logs
of wood, thereby causing excessive dilution of the caustic liquor; (_b_)
prolonged excessive dampness might create heating and deterioration
unless the hemp were properly retted; (_c_) wet hurds could not be
sieved free from sand and chaff. Should further work show that the first
two reasons need not be taken into consideration, the third objection
might be overcome by sieving the hurds before baling. Even then, it is
probable that baled hurds stored in the open would accumulate and retain
considerable dirt from factory chimneys, locomotives, and wind. Checked
pulp wood exposed in the open invariably suffers from these causes.

In the preparation of the raw material for the digesters there is
likewise considerable difference between hurds and poplar wood. The
former apparently requires only a moderate sieving to remove sand and
chaff, which operation doubtless would require only a small amount of
labor and the installation of some simple machinery of low power
consumption. In preparing poplar for digestion, the 4-foot logs are
chipped by a heavy, comparatively expensive chipper of high power