Eucalyptus has been used for pulp wood in Australia. As eucalyptus grows rapidly, there is a tendency among many other countries to use it for the pulp wood. For the shortage of soft wood, or red pine etc., eucalyptus has attracted many attentions in our country, too.
This report is our experimental result to study whether eucalyptus is useful raw material for the paper. In this experiment we used blue gum (Eucalyptus globulus Labill).
These results are outlined as follows;
(1) The average fiber length of blue gum was about 0.76 mm and the volume weight was 0.68 g/cm³ (oven dry).
(2) The chemical composition of blue gum was about the same as the general hard wood.
(3) We got SP, K P and NSSCP from blue gum. And the iron is in danger of corrosion by tannin so we think when the non-lining iron digester is used to cook blue gum by the neutral sulphite semi-chemical process, it needs to extract the tannin previous to the cooking for its high tannin content.
(4) The above pulps were bleached by the three-stage bleaching method (chlorine, caustic soda, and calcium hypochlorite). Every pulp was bleached easily and the colour retention was little.
(5) Then the pulp strengh was tested. Except S P, both the bleached and unbleached, the eucalyptus pulps were superior to the unbleached red pine S P in strength.
As the conclusion, eucalyptus K P and NSSCP is suitable pulp for paper. But it must be mind that these results are for blue gum only, and the all kinds of eucalyptus are not always suitable raw material for paper.

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Kraft rayon pulp is prepared ordinarily by way of the prehydrolysis of the wood chips. Although this is an excellent process in many respects, one weak point may be mentioned. In the course of the prehydrolysis the water content of the chip is increased, and it becomes the troubles in the succeeding kraft digestion, i.e. special measures must be used in the preparation of the white liquor and the circulation and recovery of the black liquor. On account of the circumstances that the acidic prehydrolysis and the alkaline kraft digestion are carried out alternatingly in one and the same digester at much elevated temperatures respectively, the materials and the durability of the digester must be carefully studied.
When the pulp wood of moderate or rather small size are used, the following procedures may be carried out.
Prehydrolysis and digestion are carried out in its own digester respectively . The pulp wood log is directly subjected to the prehydrolysis and then chipped. By way of these procedures, the water content increase of log may be more easily controlled and reduced than that of chips. Selection of the digester materials may be more simple.
In carrying out these procedures, we were at first afraid of that the effect of the prehydrolysis may be different according to the outer or inner parts of the log and the homogeneity of the pulp in respects of its properties may not be attained . But these were disproved and we could not find any defects in the quality of the pulp, compared with that of the pulp prepared according to the ordinary prehydrolysis of the chip.

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Handsheet study was carried out by the use of TAPPI standard sheet machine.A new method was introduced into our handsheet study for the measurement of the formation of paper sheet by examining the uniformity of weight distribution throughout a definite area on the sample. The degree of deflocculation of the fiber suspension was evaluated indirectly by measuring the formation of the resultant paper. Paper sheets for the test were prepared from a lot of fiber suspension whose medium variables, such as concentration, viscosity, and degree of polymerization etc., were kept similar to those of the report I correspondingly, except the altered pulp consistency of 0.033%
The results obtained are as follows
(1) Sodium alginate and C. M. C. added to the fiber suspension are found to be effective in improving the uniformity of formation of the resultant paper.
(2) It is found that the effect of these additives on the improvement of paper formation is dependent upon their deflocculating power on the fiber suspension which was directly evaluated in the previous work, although it can be observed distinctly only in lower viscosity range of suspension but not in higher one where the difference between the effectiveness of each additive tends to disappear and the improvement of paper formation comes to a limit.

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Three bursting strength testers were compared, one was a home-made, others were imports. In order to eliminate apparent differences of results, their correlativities were calculated. But the relationship between them were found to be variable by some unknown facters.
The concentration of glycerin, pressure transference liquid, would be one of these factors which have caused the variation of data. The viscosity of glycerin is rapidly increased with its increased concentration. The time-lag may occur because of the high viscosity of the liquid and pressure of non-uniformity may work on the paper to be tested. Then the paper will be broken under its normal bursting strength.
The experiments were made with varieties of the concentrations of glycerin and we found that within about 90% was the glycerin concentration, normal was the bursting strength and over that range, low strength was determined.
These results will support our opinions.

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