Having already, in our article MEenANios, given a full account of the experiments of Desagulicrs, and of the more recent and accurate ones of Coulomb, On the Friction and Rigidity of Ropes, we shall conclude this article with two useful Tables, containing the length and weight of ropes and cables of different kinds and sizes.
Whale oil and tallow have therefore an excellent effect, particularly the former.
The following results, obtained by Mr. Chapman, show the progressive weight borne by a rope made of long wool, and the elongation which the different Lengths sustained by these weights.
When the rope broke, its returned to 264 inches, though in a former trial it stooa at 32 inches. The girt of the woollen rope was 1.8 it weighed 75 lbs. for every 120 fathoms. Mr. Chaj.man computes, that woollen ropes may be about id of the strength of good hempen ones, and 'Ids the strength of common white ones.
The following experiments were made by Mr. Chap man on the elasticity of ropes of different kinds, when strained with iths of their breaking stress.
The three kinds of rope last mentioned, stretched on an average I inch in 24 with a fifth of their break ing stress, which is from 2 to s lbs. of the whole stretching of the registered strand laid ropes, but only from 4ths to 4th of the stretching of the common made shroud ropes.
In May 1805, Sir Joseph Banks being anxious to try teak tar for ropes, two three-inch ropes were made of the same yarns, one with teak tar, and the other with common tar. They were then placed in the same storehouse, and were broken September 28th, 1807.
Common tarred rope broke with 3848 pounds.
That made with teak tar broke with 5980 Those who wish for farther information on the subject of ropemaking, are referred to the following works: patent of March 1798, Repertory of 3rts, 1st series, vol. ix. Mr. Chapman's patent of Nov. 1798, Reper tory of .qrts. Mr. Curr's patent for flat ropes, Reper tory of :lets, 1st series, vol. x. p. 361. Mr. Mitchell's patent or 1799, in the Repertory of .drts, 1st series, vol. xi. p. 302. Mr. Huddart's patent of August, 1799, Repertory of .drts, 1st series vol. xii. Mr. Hud dart's patent of July 1800, Repertory of Arts, 1st se ries, vol. xiv. Messrs. Mitchell's parent of 1802, Repertory of .drts, 2d series, vol. viii. p. 241. Mr. Walker's patent of 1806, Repertory of .drts, al series, No. 70. Huddart's Remarks on the Patent Registered Cordage, Lond. 1800. Mr. Chapman's Treatise on the progressive endeavours to improve the Manufacture and Duration of Cordage, Lond. 1808.