35.4
320 | 29.3| 107.5| 84.2| 5| 170|/
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[Footnote 3: Stock not used; dirty.]

Discussion of the various cooks will be given in connection with the
descriptions of those paper tests in which the stocks from the cooks
were used, since a stock and its cooking condition can be judged
adequately only after it has been put through the various processes and
into the finished sheet of paper.

The first test consisted in making four separate cooks, Nos. 293, 294,
295, and 296, of approximately 300 pounds each, dividing the total stock
into two parts and making two separate paper tests. The first test was
made primarily in order to learn some of the qualities and
characteristics of the stock and to get the machinery equipment adjusted
properly. The yield of fiber was not determined in this preliminary
test, since the knowledge of it was not essential at this stage of the
work. The cooked stock which was emptied into the drainer to be washed
free from black liquor was composed largely of whole pieces of hurds,
but only slight pressure between the fingers was required to crush the
pieces. In the case of wood, this condition ordinarily would indicate
undercooking, but might not in the case of hurds. Further observation on
the action of the cooked stock during subsequent processes was necessary
in order to judge of its quality or the suitability of the cooking
conditions. The total cooked stock, about 500 pounds, was divided into
two portions of 200 and 300 pounds, respectively, and work was continued
on them separately. The 200-pound test, designated as run No. 135, was
put into a 350-pound washing engine, washed one hour, and given a total
light brush of 2-1/4 hours. The washing removed a great amount of dirt,
but the engine did not reduce the hurd stock as much as was desired.
After heating the stock in the beater to 40 deg. C., it was bleached with
bleaching-powder solution, 94 gallons at 0.418 pound bleach per gallon,
equivalent to 19.7 per cent of the fiber. This percentage of bleach is
regarded as too high for stock intended for book-paper manufacture, and
subsequent cooks therefore were given harder treatment in order to
reduce this figure. After draining and washing free from bleach
residues, the stock was furnished in the beater with 13 per cent of
clay, 1 per cent of resin size, and 2.5 per cent of alum, was tinted