ROPE-MAKING.

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rigging, are from a quarter of an inch to somewhat more than athird of an inch in circumference, or of such a size that 160fathoms weigh from three and a half to four pounds when white.The different sizes of yarns are named from the number of themcontained in a strand of a rope of three inches in circumference.l<'ew are so course that sixteen will make a strand of British cord-age ; eighteen is not imfrequenl for cable-yarns, or yarns spunfrom harsh and coarse hemp; twenty-five is, we believe, thefinest size which is worked up for the rigging of a ship. 'The nextoperation is to form the rope-yarns into ropes, cords, or lines.That we may have a clear conception of the principle which re-gulates this part of the process, wc shall explain the simplest pos-sible case, the union of two yarns into one line. This is not avery usual fabric for rigging, but we select it for its simplicity.When hemp has been split into very fine fibres by the hatchel, itbecomes exceedingly soft and pliant, and after it has lain for sometime in the form of tme yarn, it may be unreeled and thrown loose,without losing much of its twist. Two such yarns may be put onthe wheel of a spinning-wheel, and thrown, like flaxen yarn, so asto make sewing thread. It is in this way, indeed, that the sail-maker’s sewing thread is manufactured; and when it 1ms beenkept'on the reel, or on balls or bobbins, for some time, it retainsits twist as well as its uses require. But this is by no means thecase with yarns spun for great cordage, The hemp is so elastic,the number of fibres twisted together is so great, and the diameterof the yarn (which is a sort of lever on which the elasticity of thefibre exerts itself) is so considerable, that no keeping will makethe fibres retain this constrained position. The end of a rope-yarnbeing thrown loose, it will immediately untwist, and this withconsiderable force and speed. It would, therefore, be a fruitlessattempt to twist two such yarns together ; yet the ingenuity ofman has contrived to make use of this very tendency to untwistnot only to counterac t itself, but even to produce another and apermanent twist, which requires force to undo it, and which willrecover itself when this force is removed. Every person mustrecollect that, when he has twisted a packthread very hard withhis fingers between his two hands, if he slackens the thread bybringing his hands nearer together, the packthread will immediate-ly curl up, running into loops or kinks, and will even twist itselfinto a neat and firm cord. The operation of uniting the strandswith a permanent twist is called laying or closing : the latter termbeing chiefly appropriated to cables and other very lar»e cordan-e.Lines and coidnge lesi than one inch and a half in circumferenceare laid at the spinning-wheel. The workman fastens the ends ofeach of two or three yarns to separate whirl-hooks. The remoteends are united in a knot. This is put on one of the hooks of aswivel called the loper, and care is taken that the yarns are ofequal lengths and twist. A piece of soft cord is put on the otherhook of the loper; and, being put over a pulley several feet fromthe ground, a weigh,t is hung on it, which stretches the yarn.When the workman sees that they are equally stretched, he or-ders the wheel to be turned in the same direction as when twin-ing the yarns. This would twine them harder; hut the swivel ofthe loper gives way to the strain, ami the yarns immediately twistaround each other, and form a line or cord. In doing this theyarns lose their twist. This is restored by the wheel. But thissimple operation would make a very bad line, which would be-slack, and would not hold its twist; for, by the turning of the lo-peri the strands twist immediately together, to a great distancehorn the loper. By this turning of the loper the yarns are un-twisted, The wheel restores their twist only to that part of theyarns that remains separate from the others, but cannot do it inmat part where they are already twined round each other, becausetneir mutual pressure prevents the twist from advancing, (t is,therefore, necessary to retard this tendency to twine, by keepingthe yarns apart. This is done by a little tool called the top. ItH a truncated cone, having three or more notches along its sides,a , a handle called die staff. This is pul between the strands,i-ie small end next the loper, and it is pressed gently into the an-g,e .onned by the yarns which lie in the notches. The wheel-eiiig now turned, the yarns are more twisted or hardened up, andleir pressure on the top gives it a strong tendency to come out oftk ,(! a -iii a ,. , a ' so t° turn round. Thu workman does not allowis uU he thinks the yarns sufficiently hardened. Then lie yieldsthe pressure, and the top comes away frovoi.. tv.—NO. I9u.

ray from the swivel, which im-

mediately turns round, and the line begins to lay. Graduallyyielding to this pressure, the workman slowly comes up towardsthe wheel, and the laying goes on, till the top is at last close tothe wheel, and the work is done. In the mean time, the yarnsare shortened, both by the twining of each-and the laying of thecord. The weight, therefore, gradually rises. The use of thisweight is to oblige the yarn to take a proper degree of twist, andnot run into kinks. The process for laying or closing large cord-age is considerably different from this. The strands of which therope is composed consist of many yarns, and require a consider-able degree of hardening. This cannot be done by a whirl drivenby a wheel-band ; it requires lire power of a crank turned by thehand. The strands, when properly hardened, become very scut,and when bout round the top are not able to transmit force enoughfor laying the heavy and unpliant rope which forms beyond it.The elastic twist of the hardened strands mus', therefore, be assist-ed by an external force. The first operation is warping the yarns.At each end of the walk are frames called warping-frames, whichcarry a great number of reels or winches filled with rope-} am.The foreman of the walk takes off a yarn-end from each, till hehas made up the number necessary for his rope or strand, andbringing the ends together, lie passes the whole through an iron-ring fixed to the top of a stake driven into the ground, and drawsthem through : then a knot is tied on the end of the bundle, anda workman pulls it through this ring till the intended length isdrawn off the reels. The end is made fast at the bottom of thewalk, or at a piece of machinery called the sledge, and the fore-man comes back along the skuin of yarns, to see that none arehanging slacker than the rest. He takes up in his hand such asare slack, and draws them tight, keeping them so till lie reachesthe upper end, where he cuts the yams to a length, again adjuststheir tightness, and joins them all together in a knot, to which hofixes the hook of a tackle, the other block of which is fixed to afirm post, called the warping-post. The skain is well stretchedby this tackle, and then separated into its different strands, Eachof these is knotted apart at both ends. The knots at their upperends are made fast to the hooks cf the cranks in the tackle-board,and those at their lower ends are fastened to the cranks in thesledge. The sledge itself is kept in its place by a tackle, by whichthe strands are again stretched in their places, and every tiling ad-justed, so that the sledge stands square on the walk, and then aproper weight is laid on it. The tackle is now cast oil', and thecranks are turned at both ends, in the contrary direction to thetwist of the yams. (In some kinds of cordage the cranks areturned the same way with the spinning-twist.) By this the strandsare twisted and hardened up; and as they contract by this opera-tion, the sledge is dragged up the walk. When "the foremanthinks the strands sufficiently hardened, which he estimates by themotion of the sledge, lie orders the heavers at the cranks to stop.

1 he middli -strand at the sledge is taken off from the crank. Thiscrank is taken out, and a stronger one put in its place. The otherstrands are taken off from their cranks, and all are joined on thehook which is now in the middle-hole. The top is then placedbetween the strands, and, being pressed home to the point of theirunion, the carriage is placed under it, and it is iirr’nly fixed down.Some weight is taken off the sledge. The heavers now begin toturn at both ends. Those at the tackle-board continue to turn asthey did before; but the heavers at the sledge turn in the oppo-site direction to their former motion, so that the cranks at bothends are now turning one way. By the motion of the sledge-crankthe top is forced away from the knot, and the rope begins to close.The heaving at the upper end restores to the strand the twistwhich they are constantly losing by the laying of the rope. Theworkmen judge of this by making a clmlk-mark on intermediatepoints of tire strands, where they lie on the stakes which are setup along the walk for their support. If the twist of the strands isdiminished by the motion of closing, they will lengthen, and thechalk-mark will move away from the tackle-board: but if thetwist increases by turning the cranks at the tackle-board, thestrands will shorten, and the mark will come nearer to it. a's thedosing of the rope advances, the whole shortens, and tin- sled®eis dragged up the walk. The top moves faster, and at last reachesthe upper end of the walk, the rope being „ ow i a ,d. j„ t | le .mean time, the sledge has moved several fathoms from the placewhere it was when the laying began. These motions of the^ ^ *• sledge