The Steel of 318,823 T. S. was .047 inch diam., and had an extension of only 0.3 per cent; that of 103,272 T. S, was .107 inch diam. and had an extension of 2.2 per cent. One lot of .044 inch diam. had 267,114 T. S., and 5.2 per cent extension. Hemp Ropes, Untarred.-15 tests of ropes from 1.53 to 6.90 inches circumference, weighing 0.42 to 7.77 pounds per fathom, showed an ultimate strength of from 1670 to 33,808 pounds, the strength per fathom weight varying from 2872 to 5534 pounds. Hemp Ropes, Tarred.--15 tests of ropes from 1.44 to 7.12 inches circumference, weighing from 0.38 to 10.39 pounds per fathom, showed an ultimate strength of from 1046 to 31,549 pounds, the strength per fathom weight varying from 1767 to 5149 pounds. Cotton Ropes.-5 ropes, 2.48 to 6.51 inches circumference, 1.08 to 8.17 pounds per fathom. Strength 3089 to 23,258 pounds, or 2474 to 3346 pounds per fathom weight. Manila Ropes.-35 tests: 1.19 to 8.90 inches circumference, 0.20 to 11.40 pounds per fathom. Strength 1280 to 65,550 pounds, or 3003 to 7394 pounds per fathom weight. Tensil per sq 3 4 38 42 The grades are numbered 1 to 6, but the weights are not giv strengths vary considerably, even in the same number. Marbles.-Crushing strength of various marbles. 88 tests, Specimens were 6-inch cubes, or columns 4 to 6 inches diameter, a 12 inches high. Range 7542 to 13,720 pounds per square inch. Granite.-Crushing strength, 17 tests; square columns 4 x 4 a 4 to 24 inches high, 3 kinds. Crushing strength ranges 10,026 pounds per square inch. (Very uniform.) Stones.-(Probably sandstone, local names only given.) 11 tests, 6 x 6, columns 12, 18 and 24 inches high. Crushing strength from 2105 to 12,122. The strength of the column 24 inches long is g from 10 to 20 per cent less than that of the 6-inch cube. Stones.-(Probably sandstone) tested for London & Northweste way. 16 lots, 3 to 6 tests in a lot. Mean results of each lot rang 3785 to 11,956 pounds. The variation is chiefly due to the stones bei different lots. The different specimens in each lot gave results whi erally agreed within 30 per cent. Bricks.-Crushing strength, 8 lots; 6 tests in each lot; mean ranged from 1835 to 9209 pounds per square inch. The maximum va in the specimens of one lot was over 100 per cent of the lowest. In t uniform lot the variation was less than 20 per cent. Wood.-Transverse and Thrusting Tests. 5888 an 5259 and 3875 and Portland Cement.-(Austrian.) Cross-sections of specimens inches for pulling tests only; cubes, 3 x 3 inches for thrusting tests; we ATERIALS. MISCELLANEOUS TESTS OF MATERIALS. 30 98.8 pounds per imperial bushel; residue, 0.7 per cent with sieve 2500 mesh per square inch; 38.8 per cent by volume of water required for mixing; ti of setting, days; 10 tests to each lot. The mean results in lbs. per sq. were as follows: Cement 1 Cement, 1 Cement, alone, 2 Sand, 3 Sand, Thrusting. Thrusting. Thrusting. Cement 4078 to 5412 5648 to 8869 4570 to 7750 Age. 10 days alone, Pulling. 376 9946 20 days 2910 420 6389 30 days 3342 3852 to 5159 4271 to 4343 -, 113 to 408 pounds per inch; e weights are not given. The marbles. 38 tests, 8 kinds. uare columns 4X4 and 6X4 ength ranges 10,026 to 13,271 es only given.) 11 kinds, 4 Crushing strength ranges n 24 inches long is generally ch cube. ondon & Northwestern Railits of each lot ranged from Tue to the stones being from lot gave results which gen s in each lot; mean results The maximum variation of the lowest. In the most nt. sting Tests. Portland Cement.-Various samples pulling tests, 2x 21⁄2 inch ross-section, all aged 10 days, 180 tests; ranges 87 to 643 pounds per squa inch. TENSILE STRENGTH OF WIRE. Special qualities of tempered and improved caststeel wire may attain............... MISCELLANEOUS TESTS OF MATERIALS. Reports of Work of the Watertown Testing-machine AAY 34 1012 102 134 39,300 6 134 47,180 47.0 41,000 5 0,520 1403 5438 11-16 10 2478 11-16 657 10 7,948 to 13-16 to .152 ,856 to 790 1505 10 3423 2473 1 1-16 to 1012 1 1-16 101% to 1779 084 2656 1190 624 to 13-16 to 3890 10% 13-16 15-16 1012 6 10 8169 to 10.785 5888 and 7284 6769 5978 912 62,180 57,215 55.0 52,445 63.4 62,590 52,445 63.8 § Butt-joint. The efficiency of the joints is found by dividing the maximum tensile stress on the gross sectional area of plate by the tensile strength of the material. COMPRESSION TESTS OF 3 x 3 INCH WROUGHT-IRON BARS. The steel was made by the Cambria Iron Company, and the eye-bar heads made by Keystone Bridge Company by upsetting and hammering. All the bars were made from one ingot. Two test pieces, 34-inch round, rolled from a test-ingot, gave elastic limit 48,040 and 42.210 pounds; tensile strength, 73,150 and 69,470 pounds, and elongation in 8 inches, 22.4 and 25.6 per cent. respectively. The ingot from which the eye-bars were made was 14 inches square, rolled to billet, 7 x 6 inches. The eye-bars were rolled to 6% X 1 inch. Chemical tests gave carbon .27 to .30; manganese, .61 to .73; phosphorus, 074 to .098. The average tensile strength of the 34-inch test pieces was 71,310 lbs., that of the eye-bars 67,230 lbs., a decrease of 5.7%. The average elastic limit of the test pieces was 45,150 lbs., that of the eye-bars 36,402 lbs., a decrease of 19.4%. The elastic limit of the test pieces was 63.3% of the ultimate strength, that of the eye-bars 54.2% of the ultimate strength. COMPRESSION OF WROUGHT-IRON COLUMNS, LATTICED BOX AND SOLID WEB. * Pins in centre of gravity of channel bars and continuous plate, 1.63 inches from centre line of channel bars. + Pins placed in centre of gravity of channel bars. EFFECT OF COLD-DRAWING ON STEEL Three pieces cut from the same bar of hot-rolled steel: 1. Original bar, 2.03 in. diam., gauged length 30 in., tensile strength 55,400 lbs. per square in.; elongation 23.9%. 2. Diameter reduced in compression dies (one pass) .094 in.; T. S. 70,420; el. Compression test of cold-drawn bar (same as No. 3), length 4 in., diam. 1.808 in.: Compressive strength per sq. in., 75,000 lbs.; amount of compression .057 in.; set .04 in. Diameter increased by compression to 1.821 in. in the middle; to 1.813 in. at the ends. Tests of Cold-rolled and Cold-drawn Steel, made by the Cambria Iron Co. in 1897, gave the following results (averages of 12 tests of each): Before cold-rolling, E. L. 35,890 T. S. 59,980 El. in 8 in. 28.3% Red. 58.5% After 66 After cold-drawing, 66 72.580 46 79,830 66 9.6 66 8.96 34.9" 34.2" The original bars were 2 in. and in. diameter. The test pieces cut from the bars were 34 in. diam., 18 in. long. The reduction in diameter from the hot-rolled to the cold-rolled or cold-drawn bar was 1/16 in, in each case. |