Refiued bast of “ Kozo” (Sirokawa) was heated at 100°C with varying quantities of caustic sod (115% against bast) for varying times (0.55.0 hrs) The waste liquor was subjected to conductonietric and poteutiometric titrations with normal solutions of hydrochloric acid and sodium hydroxide respectively. From the analytical results the distribution of the original caustic soda was estimated, i.e. the combined anlkali with weak acidic organic substance in the liquor, free hydroxide, in the liquor and the alkali retained in the residual bast fibre. Free organic acid was also estimated, when the amount of soda was insufficient. Organic matters dissolved in the liquor, was also estimated, and the ratio with combined alkali was calculated. The ratio was approximately equal to that of one hexose group against one NaOH molecule, and was almost independent of the amount of soda used and the time of boiling. Orgainc acidic substance seems to be composed of mixtures of acids, the dissociation constants of which lie between 10^-510^-6 and 10^-810^-9.

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The writer calculated the efficiency a of fly-wheel and then the diameter of shaft from torsion moment and bending moment. He studied the ventilating work caused by chipper and commented on if. He explained the utility of raw wood when chipper is used.

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The writer shows 5 plans or ways of reconstruction which can be easily carried out on some parts of paper making machinery.
1) A reconstruction plan of a washing drum used for a drum washer beater, or a potcher, whose washing time can be shortened.-The filtering part is separated from the draining part, and each part is caused independently to operate effectively.
2) A plan of felt washer equipped with a suction box in a washing vat.-A suction box is fitted to the botton of a washing vat. Felt is washed with water which is continually given from above and is made to suck up filthy water through felt.
3) A plan of Fourdrinier Paper Machine regulating the uniformity of web.-A suction box is fitted directly under the sluice in a wet part of Fourdrinier Paper Machine. The suction box is caused to filter artificially whether stuff is wet or free, and to regulate the uniformity of web. (To be continued.)

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We have lately got many a good study on pitch troubles. Such studies are deeply required in this country where red pine is used as main resources of pulp. Both of these articles try to explain the nature of pitch troubles on practice and give an important suggestion on a method of eliminating them.

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The writer explains when wood pulp was for the first time imported to Japan and used to produc Japanese type paper. Philologically studying the histoy of various pulp in this country, he gives an explanation of the interesting data concerning Karafuto Pulp which were unknown up to this time. The writer is an authority on the history of paper manufacturing in this country.

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