ROF 



When the rope is made very thick, it is called a cable ; 

 and when very fmall, a cord. 



Though it be difficult to give a certain account of the 

 forces required to bend ropes of different diameters, in mak- 

 ing them go round bodies of different bigneffes, yet to make 

 no allowance for the lofs of motion fuftained thereby, would 

 be as prejudicial to the practice of mechanics, as it would be 

 to overlook the friftion of the parts of engines. The diffi- 

 culty of afcertaining this force arifes from the different 

 materials of which they are made, their different ltiffnefs 

 according as they are more or lefs twilled ; and fometimes 

 from the temperature of the air, as to moitture and 

 drynefs. 



Dr. Defao-uliers has computed the forces required to bend 

 ropes of different diameters, ftretched by different weights, 

 round rollers of different bigneffes. The rcfult of his expe- 

 riment is expreffed in the following table. 



On the whole, it has been found by experiments, that the 

 difficulty of bending a rope round a roller decreafes direftly 

 as the diameter of the roller increafes, or is, inverfely, as 

 the diameter of the roller. See Defaguliers, Experim. 

 Phil. vol. i. p. 233, &c. See alfo Cordage. 



A Table, fhewing how many fathoms, feet, and inches 

 of a rope of any fize, under fourteen inches, makes a 

 hundred weight, with the ufe of the table. 



R O P 



Suppofe I want to know how much of eight -inch and 

 quarter rope will make a hundred weight ? Find 85 under 

 inches, and againft it, in the fixth column, you find 708, 

 which (hews in a rope of 85, there will be feven fathoms 

 eight inches required to make one hundred weight. 



A Table, fhewing the weight of any cable or rope of 

 1 20 fathoms in length, and for every half inch from three 

 inches to twenty-four in circumference. 



The greateft confumption of rope is ufed for the purpofes 

 of navigation in rigging of (hips : where, though ropes 

 include the whole cordage, there are feveral particularly deno- 

 minated, and which have particular names given to them ; 

 as follow. 1. Awning-ropes are the ridge and fide -ropes. 

 The ridge-rope reeves through the trucks feized along the 

 middle of the awning ; the fide-ropes reeve through the 

 trucks feized along the fide of the awning. By thefe ropes 

 the awnings are fpread between the malts. 2. Bell-rope, 

 nine or ten feet in length, which fplices round a thimble in 

 the eye of the bell-crank. In the middle of the rope is a 

 diamond-knot, and at the end a double wall-knot crowned. 

 3. Boat -rope, or painter, that by which the boat is towed 

 at the ftern ; it fplices with a thimble to a ring-bolt infide the 

 ftem. 4. Bolt-rope, the rope fewed to the edg"S of the fails, 

 as the head-rope, foot-rope, and leech-rope. 5. Breaft-rope, 

 that fattened along the laniard of the (hrouds, for fafety, when 

 heaving the lead in the chains. 6. Bucket-rope, that which 

 is fattened to the bucket for hauling up water. 7. Buoy 

 rope, the one fattened to the buoy and crown of the anchor. 

 8. Davit-rope, the ladling which fecures the davit to the 

 (hrouds when out of ufe. 9. Entering-ropes have their 

 upper end thruft through the eye in the iron-ftantions at the 

 gangways, and are walled and crowned ; and diamond-knots 

 are made at every nine inches afunder in the whole length. 

 10. Grapnel-rope, that which is bent to the grapnel, by 

 which the boats ride. 11. Guilt-rope, that fattened to an 

 eye-bolt in the (hip's fide, and to the outer end of a boom 

 projecting from the (hip's fide, by guys, to keep the boats 

 clear from rubbing againft the fides. 12. Heel-rope, that 

 which hauls out the bowfprit of cutters, and the jib and 

 ftudding-fail boom. 13. Man-ropes are for the fecurity of 

 the men going out upon the bowfprit. 14. Parral-ropes are 

 to connedt the ribs and trucks of the parral together. 

 15. Paffing-ropes lead round the (hip through the eyes in the 

 quarter waift and forecaftle-ftantions, have one end (topped 

 through the eye of the gangway-ftantion, with a wall-knot 

 crowned, and are fet forward through an eye-bolt in the 

 knight-head with a laniard, having a thimble turned into the 

 end. 16. Ring-ropes are occafionally made fall to the ring 

 or ftopper-bolts in the deck, and by crofs turns round the 

 cable, to confine it more fecurely in ftormy weather. 

 17. Slip-rope is to trice the bight of the cable into the 



heads ; 



