ROPE-MAKING.

sledge and top must be exactly adjusted to each other. The ropemust be of a certain length. Therefore the sledge must stop at acertain place. At that moment the rope should be laid ; that isthe top should be at the tackle-board. In this consists the ad-dress of the foreman. He has his attention directed both ways.He looks at the strands, and when he sees any of them hangingslacker between the stakes than the others, he calls to the heaversat the tackle-board to heave more upon that strand. He finds itmore difficult to regulate the motion of the top. It requires aconsiderable force to keep it in the angle of the strands, and it isalways disposed to start forward. To prevent or check this, somestraps of soft rope are brought round the staff of the top, and thenwrapped several times round the rope behind the top, and kepifirmly down by a lanyard or bandage. This both holds back thetop, and greatly assists the laying of the rope, causing the strandsto fall into their places, and keep close to each oilier. This issometimes very difficult, especially in ropes composed of morethan thrte strands. It will greatly improve the laying of the rope,if the top have a sharp, smooth, tapering pin of hard wood, point-ed at the end, projecting so far from the middle of its smaller end,that it gets in between the strands which are closing. This sup-ports them, and makes their closing more gradual and regular.The top, its notches, the pin, and tire warp or strap, which is lap-ped round the rope, are all smeared with grease or soap to assistthe closing. The toreman judges of the progress of closing chieflyby h'is acquaintance with the walk, knowing that when the sledgeis abreast of a certain stake the top should be abreast of a cer'amother slake. When he rinds the top too far down the walk, he'slackens the motion at the tackle-board, and makes the men turnbriskly at the sledge. By this the top is forced up the walk, andthe laying of the rope accelerates, while die sledge remains in thesame place, because the strands are loosing their twist, and arelengthening, while the closed rope is shortening. When, on theother hand, he thinks the top too far advanced, and fears it will beat the head of the walk before the sledge lias got to its. properplace, lie makes the men heave briskly on the strands, and the'heavers at the sledge-crank work softly. This quickens tile mo-tion of the sledge by shortening the strands ; and by thus compen-sating what has been overdone, the sledge and top come to theirplaces at once, and the work appears to answer the intention.But tins is a bad method of proceeding. It is evident, that if thestrands be kept to one decree of hardness throughout, and theheaving at the sledge uniformly continued, the rope will beuniform. It may be a little longer or shorter than was intended,and the laying may be too hard in proportion to the twist of thestrands, in which case it will not keep it ; or it may be too slack,and the rope will tend to twist more. Either of these faults arediscoverable by slackening the rope before it comes off the hooks,end it may then be corrected. But if the error in one place becompensated by that in another, this will not he easily seen beforetaking off the hooks; and if it he a large and stiff rope, it willhardly ever come to an equable state in its different parts, but willbe apt to run into loops during service. The cordage, of whichwe have been describing the manufacture, is said to be hawser-laid. It is uncommon to make ropes of four strands. These areused for shrouds, and this cordage is therefore called shroud-laidcordage. A rope of the same size and weight must be smootherwhen it has four strands, because the strands are smaller: but itis more difficult to lav close. There is another species of cordagein very general use. A rope of two or more strands may be usedas a strand, in order to compose a still larger rope ; and in thismanner are cables and other ground-tackle commonly made ; forthis reason such cordage is called cable-laid cordage. The pro-cess or eable laying hardly differs from that of hawser-laying.Three ropes, in their state of permanent twist, may be twisted to-gether ; but they will not hold it, like fine thread, because theyme stiff and elastic. They must therefore he treated l.ke strandsfor a hawser. We must give, them an additional twist, which willdispose them to lay 01 close themselves ; and this disposition mustbe aided by the workmen at the siedge. We sav the twist shouldbe an addition to their twist as a rope. A twist in the oppositedirection will indeed give them a disposition to close behind thetop ; but this will be verv small, and the ropes (now strands) willbe exceedingly open, and will become more open in laying. Thetwist is therefore given in the direction of their twist as a rope, or

opposite to that of the primary strands, of which the ropes arecomposed These primary strands are therefore partly untwistedin cable-laying a rope, in the same manner as the yarns are un-twisted in the usual process of lope-making. The methods oftarring practised in different rope-walks are so ext eedingly differ-ent, that we can hardly enumerate them, or even give a generalaccount of them. It is evidently proper lo tar in the slate of twineor yam, this being the only way that the lump could be uniformlypenetrated. The yarn is made to wind oil one reel, and havingpassed through a vessel containing hot tar, it is wound up on ano-ther reel ; and the superlluous tar is taken off by passing througha hole surrounded with spungy oakum : or it is tarred in skains orhauls, which are drawn by a capstern through the tar-kettle, andthrough a hole formed of two plates of metal, held together by itlever loaded with a weight. It is beyond a doubt, that tarredcordage when new is weaker than white, and that the differenceincreases by keeping. 'I he following experiments were made bvMr. Du Hamel, at Rochefort, on cordage of three inches (French )in circumference, made of the best Riga hemp:

, Aug. 8,

White ..

Tarred.

Broke with

4500 pounds.

3400 pounds.

4900

3300

4800

3250

1743, April 25,

4000

3500

5000

3400

5000

3400

1746, Sept. 3,

3800

3’.00

4000

2700

4200

2800

A parcel of while am! tarred cordage was taken out of a quan-tity which had been made February 12, 1740. It was laid up iiithe magazines, and comparisons were made from lime to time asfollows:

White bore. Tarred bore. Di(F-

1740, April 14, 2045 pounds. 2312 pounds. 333

1747, May 18, 2702 2155 ■ 607

1747, Oct. 21, 2710 2050 000

1748, June If), 2515 1752 823

1748, Oct. 2, 2425 1837 588

1749, Sept. 25, 2917 1865 1052

Mr. Du Hamel says, that it is decided by experience, 1. Thatwhite cord; ge in continual service is one-third more durable thantarred. 2. 'That it retains its force much longer white kept instore. 3. That it resists the ordinary injuries of the weather one-fourth longer. In 1758, the shrowds and stays of the Sheer hulkat Portsmouth dock-yard were overhauled, and when the wormingand service were taken oil, they were found to be of white cord-age. On examining the store-keeper’s hooks, they were found tohave been formerly the shrowds and rigging of the Koval Wil-liam, of 110 guns built in 1715, and rigged in 1716. She wasthought too heavy and unlit for sea, and unrigged, and her storeslaid up. Some lew years afterwards, her shrowds and stays werefitted on the Sheer luilk, where they remained in constant andi very hard service for about thirty years, while every tarred ropeabout her had been repeatedly renewed. Tin 's fact was vouchedby Mr. Brown, boatswain of the Koval William during the war1758, &c. It may then be asked, Why do we tar cordage? Wethus render it more nnpliant, weaker, and less durable. It ischiefly serviceable for cables and ground-tackle, which must beooiitiimalty wetted, and even soaked. The result of careful'obser-vation is, 1. That white cordage, exposed to be alternately verywet and dry, is weaker than tarred cordage. 2. That cordagewhich is superficially tarred is constantly stronger than what e'tarred throughout, and it resists bel'er the alternatives of wet anddry. N. U. The shrowds of the Sheer hulk were well tarred andblacked, so that it was not known that they were of while.cordage.Tar is a curious substance, miscible completely w ith water. At-tempts were made to anoint cordage with oils and fats which donot mix with water. 1 his was expected to duiend them from it*pernicious effects. But it was distinctly found that these mattersmarie (lie fibres of hemp glide so easily on each other, that it w 2 ®hardly possible to twist them permanently. Before they graspedeach other so hard that they could not be drawn, they were strain*ed almost to breaking.

rore-yarn,