GROUND-WOOD PULP. ot 
of white water used and determining the wood fiber in a sample of it. 
This proved rather unsatisfactory, and was discontinued on account 
of the difficulty in removing the wood fiber from the white water 
sample. 
_ The yield of pulp has been calculated to a basis of 100 cubic feet of 
solid rossed wood, this factor being thought more satisfactory and 
accurate than a epee cord, and representing approximately the 
solid content of a piled cord of 2-foot rossed wood containing 128 
cubic feet. 
| TESTS ON THE PAPER. 
The sample of pulp to be run into paper was first shredded and the 
‘moisture determined. The required amount was then weighed out 
and mixed and beaten with a weighed amount of bleached spruce 
‘slow-cook sulphite. In some runs, particularly those made on some 
of the pulps made from cooked woods, the sulphite was dispensed 
with. The mixture, usually 20 per cent sulphite to 80 per cent 
ground wood, was beaten until the fibers were separated, generally 
‘about 1 hour. The stock was then run out on the paper machine 
and an uncalendered sample was taken for strength and color tests. 
_ No size, color, or loading was added to any of the sheets, the desire 
being to present the pulps made from different woods and under 
‘different conditions in as nearly comparable conditions as possible. 
The uncalendered samples of paper were tested for tensile strength, 
lengthwise and crosswise, by means of a Schopper breaking length 
tester, and for bursting aman by means of a Mullen tester. The 
‘color tests were made with an Ives tintphotometer and measure- 
ments were made of the thickness of the sheet and weight per ream. 
‘ EFFECT OF PRELIMINARY TREATMENT OF SPRUCE. 
, Spruce has been used for many years as a raw material for ground- 
wood pulp, but the effect of the production of pulp from it under 
| varying conditions has never been given very careful study. Depend- 
‘ing on the quality of the product desired, different conditions of 
‘grinding must be selected, and in some cases the wood must even be 
‘given a cooking treatment prior to grinding. In the manufacture of 
container board, where great strength is desired and the color is of 
lesser consequence, strength is ahaa increased by the additioa of 
sulphite or sulphate ply screenings, or old paper stock. In the 
manufacture of news print paper, strength is desired too, but not 
nearly so much strength, the color, yield, and finishing characteristics 
here being the prime consideration. The work which has been done 
on spruce has been carried on with the idea of attempting to increase 
the efficiency of grinding both from the standpoint of reducing the 
power consumption and increasing the yield from a cord of the raw 
material in either the cooking or ordinary ground-wood process, and 
