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C—3a,

increased length of wire, or by the use of granite press-rolls in place of the wooden rolls. A representative of a paper-machinery-manufacturing firm who witnessed the tests suggested these and several other artifices which, he seemed sure, would easily remedy all difficulties encountered. Rather large quantities of sulphite were purposely used in the furnishes tried in the mill-runs, but it seems entirely possible that these quantities could be reduced in mill operation and the proportion of groundwood increased. Satisfactory papers were made on a laboratory scale, using much greater proportions of groundwood, and, in our opinion, could be reproduced in mill operation. One remarkable point was the ease with which the paper took a finish, and this factor could be capitalized by its conversion into book stock. The M.F. book paper made after the news runs had been completed furnished evidence of the practicability of this suggestion. SUMMARY OF PAPERMAKING STUDIES. In the laboratory semi-commercial tests insignis-pine groundwood and insignis-pine sulphite pulps have been blended, in various mixtures for the production of standard newsprint paper. The experimental papers were, in general, stronger than the average for American newsprint. The presence of dirt and the yellow colour inherent in the groundwood pulp lowered the quality of the paper in respect to its appearance, but had the pulpwood used in. these experiments been as free from core-rot as that employed in the commercial trials the complaints as to dirt would have been much less serious. The experimental insignis-pine papers were found to run well on a modern newspaper-press, and produce a printed paper of satisfactory quality. From both the laboratory tests and commercial paper-mill trials it is evident that a furnish of 20 per cent, insignis-pine sulphite with 50 per cent, tawa sulphite and 30 per cent, tawa groundwood. can be converted into a satisfactory newsprint paper by the use of standard mill equipment at speeds varying from 300 ft. to 450 ft. per minute. Greater speeds would undoubtedly be possible with a machine built to handle this type of stock. The colour, strength, cleanliness, and finish of the papers produced are equivalent to standard news. A certain amount of hydration or beating is necessary to reach the required strength quality in the case of tawa sulphite, and a refining effect, such as rod-mill treatment, is necessary for the elimination of shives. Minor alterations in the design of the wire, couchroll, and wet presses of a standard newsprint-paper machine would greatly improve the behaviour of the stock on the machine. The same pulps may also be employed in the production of machine-finish book (rotogravure) and dry-finish wrapping papers. Bleached European larch can, according to the laboratory semi-commercial tests, be substituted for the insignis-pine sulphite pulp in the above mixed softwood-hardwood furnish in approximately the same amount to produce a satisfactory news sheet. Bleached rimu, too, can be substituted for insignis-pine sulphite, but it is probably necessary to use a greater amount to give the required strength. Tawa cooked by the semi-chemical process did not produce an entirely satisfactory newspaper, but may possibly be used to some extent in a news furnish. SIGNIFICANCE OF STUDIES. CONCLUSIONS. The conclusions relative to each division of the work have been set down in connection with the discussion of that particular section. The major objective—namely, the production of pulps suitable for newsprint—has been attained, and the supporting evidence is considered conclusive so far as the technical features of pulping and the quality of the resulting papers are concerned. In arriving at the above conclusion newsprint pulps have been produced from insignis-pine mechanical pulp combined with insignis-pine sulphite in the customary way. This produces the standard type of newsprint of approximately 70 per cent, mechanical pulp and 30 per cent, sulphite. Other furnishes, comprising varying proportions of tawa groundwood pulp and sulphite pulps from tawa, insignis pine, rimu, and European larch (the latter two bleached), have likewise resulted in newsprint equal to available standard grades. Proportions of tawa sulphite as high as 50 per cent, have been employed, and, in combination with insignis-pine or other sulphite, sulphite to the extent of 70 per cent, of the total furnish has been used, the balance being tawa groundwood. The quality of the various papers has been evaluated by comparative strength tests, colour, and dirt determinations, &c, on both the laboratory and mill-produced samples, and on commercial products secured from a large number of sources; the printing and other press characteristics have been ascertained by actual printing tests on a high-speed press of the modern type. The production of kraft pulps from the various New-Zealand-grown conifers, the secondary object of this work, has also been accomplished. Rimu and the various pines and larch all yield very satisfactory pulps by the sulphate process, rimu particularly. It is believed that the proper selection of cooking and other conditions will produce first-quality kraft products commercially from any of the species mentioned. Bleached pulps for book paper and similar products were easily produced from tawa by both the soda and sulphite processes, and from insignis pine by the sulphite process only. The pulping of insignis pine by the sulphite process involves rather careful control, but is entirely practicable. The so-called semi-kraft process was successfully applied to rimu, insignis pine, and European larch, greatly increased pulp-yields resulting, but the colour characteristics and strength of the sheets