ROPE

a general name for all kinds of cordage formed by twisting together vegetable or animal fibres or metallic wires. That of ordinary commercial use is made of vegetable fibres. The title “rope” is correctly applied only to cordage which is more than an inch in circumference, smaller kinds being preferably designated as lines, cords, twines, etc. The fibre is obtained from a great variety of plants and “gra es.” Among the most important are Hemp proper or Cultivated Hemp, Manila Hemp, Sisal, Flax, Jute and Cotton. Hemp is used for all sizes of cordage, Flax only for small lines and cords, and Cotton for thin twine. See FLAx, Hemp and JUTE. In manufacture, the fibres are first twisted together to form a “thread” or “yarn.” The yarns are then combined by twisting them into a “strand,” and three strands combined in like manner form “rope.” All the work in a modern plant is done by machinery, numerous special proce es, twists, etc., being required for cordage for special industries and purposes. The list following gives the approximate weight and strength of cordage of the sizes named: Number of Weight of 100 Weight of 100 Strength of feet in Diameter fathoms* fathoms, tarred new ropes 4 pounds (in inches) (in pounds) (in pounds) (in pounds) (feet) (inches) 6 Thread U 14 17 450 43. 9 = ts 20 24 750 33. 12 sf % 28 34 900 21. 15 = Te 34 41 1,250 17. 18 di % 45 56 1,700 13. Circumference In inches 134 À 61 78 2,500 10. 2 5% 80 100 3,000 7. 2% 3% 101 126 3,900 6. 21% 42 125 156 4,700 5. 234 Te 151 189 5,600 4. 3 1 180 225 6,750 3.4 34 1% 211 264 7,850 2.9 3% 1% 245 306 9,150 2.4 3% 1% 281 351 10,600 2.1 4 145 325 400 11,950 1.10 414 1% 361 451 13,450 1.7 4% 1% 405 506 15,150 1.5 4% 1% 451 564 16,800 14 5 15 500 625 18,700 1.2 51% 1% 605 756 22,600 I 6 2 720 909 26,900 10 6% 24 845 1,056 31,500 81 7 2% 885 1,125 36,600 14% 71% 21% 1,125 1,406 42,000 5% 64 8 256 1,280 1,600 47,800 8% 2% 1,445 1,806 54,000 5 9 3 1,620 2,025 60,500 4% *A fathom equals six feet. Although of an antiquity reaching back toward the earliest ages of man—the art of twisting animal hair, tough gra and vegetable fibres having apparently existed among the rudest people—it is only within the last two centuries that rope-making has received the succe ful attention of mechanical inventors. The primitive wheel, the workman with a bundle of hemp strung around his waist and the slow, laborious operation of laying and twisting the strands by manual labor may still be seen in remote places. [s. 541]