£.— 3a

34

Table 6.—Laboratory Grinding Tests of New Zealand and North American Wòds: Quality and Strength of Water-leaf Pulps.

Strength of Water-leaf Pulp. Colour Analysis. Interpretation of Colour Analysis. — — Dirt 7 1 ftrinriPT- Microscopic WpioTit • Tearing. Particles Primary Hue. Secondary Hue. ™o. S P ecies - P«Ream. Bursting B —. P<* ! | "I — • (24 in n by Thickness, per Pound Per Pound & Red. Green. Blue. White. Lumi . Lumi . per Beam. learmg. per lleam Tint. nosity Tint. nojjity Cc. lb. In. Points. Orm. Grm. Number. I Per Cent. : Per Cent. Per Cent. Per Cent, i Per Cent. Per Cent. 1 Spruce .. .. .. 122 Below No. 4 86 0-0146 0-17 44-0 0-51 9 1 82 73 63 63 I Oranae 5-8 Yellow 5-0 2 Insignis pine .. .. .. 167 No. 3 96 0-0156 0-25 75-2 0-78 37 77 66 58 58 j Orange 7-0 Yellow 2-3 3 Spruce .. .. .. 88 No. 4 98 0-0146 0-28 59-2 0-60 5 83 75 66 66 j Orange 5-1 Yellow 4-5 4 Insignis pine .. .. .. 40 Between Nos. 113 0-0161 0-41 115-2 1-01 11 80 71 63 63 ! Orange 5-8 Yellow 3-2 2 & 3 5 Spruce .. .. .. 67 No. 2 97 0-0149 0-31 75-2 0-78 11 81 74 67 67 Orange 4-5 Yellow 3-2 6 Insignis pine .. .. .. 233 No. 4 92 0-0158 0"24 76-8 0-84 6 79 70 61 61 Orange 5-8 Yellow 4-1 7 Insignis pine .. .. .. 147 No. 3 86 0-0144 0-29 74-4 0-87 9 80 72 63 63 ; Orange 5-1 Yellow 4-5 8 Insignis pine .. .. .. 86 Between Nos. 101 0-0139 0-38 85-6 0-85 46 75 65 58 58 Orange 6-4 Yellow 1 -8 1 & 2 9 Spruce .. .. .. 105 Below No. 4 118 0-0153 0-27 71-2 0-61 5 84 75 64 64 Yellow 5-9 Orange 5-8 10 Tawaj .. .. .. 133 Below No. 4 86 0-0118 0-16 34-2 0-40 7 84 76 69 69 Orange 5-1 Yellow 2-7 11 Tawat .. .. .. 228 Below No. 4 228 0-0157 0-17 63-6 0-54 6 84 75 69 69 Orange 5-8 Yellow 1-4 12 Tawat .. .. .. 100 Below No. 4 104 0-0157 0-11 44-2 0-43 18 83 71 66 66 Yellow 4-5 Orange 3-8 13 Insignis pine} .. .. .. .. .. .. .. .. .. 6 82 72 63 63 Orange 6-4 Yellow 3-6 14 Insignis pine§ .. .. .. .. .. .. .. .. .. 15 ! 80 71 65 65 Oranste 4-5 Yellow 2-3 15 Tawal] .. .. .. .. .. .. .. .. .. | .. .. .. .. 16 Insignis pine} .. .. .. .. 76-5 0-0127 0-33 66-8 0-87 0 i 79 68 62 62 Orange 7-0 Yellow 0-5 17 Insignis pine§ .. .. .. .. .. 127-3 0-0189 0-37 98-0 0-77 5 ! 77 67 60 60 Orange 6-4 Yellow 1-8 18 Insignis .. .. .. .. 106-4 0-0169, 0-33 82-8 0-78 1 80 70 61 61 Orange 6-4 Yellow 3-6 P655 Commercial groundwood** .. 120 Between Nos. 57 0-0121 0-22 57-6 1-01 5 84 75 68 68 Orange 5-8 Yellow 2-3 1 & 2 P658 Commercial groundwood** .. 77 No. 2 i 36 0-0077 0-31 44-0 1-22 3 77 72 65 65 Yellow 4-1 Orange 3-2 * Based on standards selected from U.S. Department of Agriculture Bulletin No. 343. See Photomicrographs. f it was necessary to add commercial sulphite pulp (10 per cent, of the total) to the Tawa groundwood in order to run it over the Fourdrinier machine. The freeness and colour analysis were made on the pulp before mixing with the sulphite. J Wood selected free of blue stain. Centre of billets bored out and knots removed. § Wood contained blue stain. Centre of billets bored out and knots removed. || Not made into waterleaf pulp. Used for newsprint-paper runs. If Mixture of blue-stained and uninfected wood. Centre of billets bored out and knots removed. ** The strength tests on the commercial pulps were made on hand sheets.