the length of 31 feet, it becomes necessary, In order to obtain rope of greater length. SO to twine them together that the strength of any single fibre shall be itsufficient to overcome the resistance caused by the friction of the e surrounding and compressing it ; so that it will sooner break than be drawn out from the mass. This requi The best mode of supplying the hemp is in the form of a thin flat skein. When the spinner has traversed the whole length of the rope walk (or sooner, if the yarns are not required to be so long), another spinner detaches the yarn from the whirl, and gives it to a person who carries it aside to a reel ; while the second spinner attaches his own hemp to the whirl-hook. The hemp, being dry and elastic, would instantly untwist if the yarn were now set at liberty. The first spinner therefore keeps fast hold of it all the while that the reeler winds it up, walking slowly up the walk, so as to keep the yarn equally tight all the way. When it is all wound up, the spinner holds it until another is ready to follow it on the reeL Sometimes, instead of being wound on a reel as they are made, the yarns are laid together in large hooks attached to posts at the side of the walk until about four hundred are collected together, when they are coiled up in a haul or skein, in which state they are ready for tarring.
The common size of rope-yarns is from one-twelfth to rather more thau one-ninth of an inch diameter ; 160 fathoms of white or untarred yarn weighing from two and a half to four pounds.
The next process is warping the yarns, or stretching them to a given length, in order that they may, when formed into a strand, bear the strain equally. When the rope is to be tarred, that operation is usually performed upon the yarns immediately after their being warped ; as the application of tar to the yarns previous to their com bination is necessary to the complete penetration of the whole substance of the rope. The most common method of tarring the yarns is to draw them in hauls or skeins through the tar-kettle by a capstan; but sometimes the yarns are passed singly through the tar, being wound off one reel on to another, and the superfluous tar being taken off by passing the yarn through a hole surrounded with spongy oakum. Great care iy required in this process that the tar may boil neither too fast nor too slow, the common heat being from 212' to 250° Fahr. The degree of impregnation necessary depends bn the kind of cordage ; cables and water ropes needing a considerable quantity of tar, while for standing and running rigging it is sufficient that the yarns be well covered.
In making large cordage, it is not usual to twist together, at once, as many yarns as would suffice to form a rope of the required thickness; a suitable number of yarns, frequently from fifteen to twenty-five, are formed into a strand, and three or more such strands are afterwards combined into a rope. The twist of the strand is in an opposite
direction to that of the yarns of which it is composed ; in order that, as before mentioned, the tendency to untwist in the individual yarns may be counteracted, and taken advantage of to prevent the untwisting of the strand. In closing or laying the rope, three strands, or some times four, (in'which case a small central strand or heart is added) are stretched at length along the walk and attached at ono end to separate but contiguous hooks, and at the other to a single hook ; and they are twisted together by turning the single hook In a direction contrary to that of the other three. A piece of wood called a top (see fig. 3), in the form of a truncated cone, is placed between the strands, and kept during the whole operation gently forced into the angle formed by the strands, where they are united by the closing or twisting of the rope. As the rope shortens in closing, one end only of the apparatus is fixed, the other being on a moveable sledge, whose motion up the ropewalk is capable of regulation by suitable tackle attached to it, or by loading it with weights. The top also is mounted on a sledge, for doffing large cordage ; and its rate of motion may be retarded, In order to give greater firmness to the twist of the rope. The art of the ropeinaker, in this operation, consists in so regulating the various movements that the strands may receive separately at one end just as much twist as is taken out of them at the opposite end, by their twisting the contrary way in the process of combination.
Such is the method, more or lees modified by the kind of machinery employed, of forming a shroud-laid or hawser-laid rope; and such appears to have been the whole process of rope-making until cordage of very large size was called for by the progress of navigatiou. In making such it was not foUnd advisable to increase the number of yarns in a strand ; it being difficult, when their number is very great, to throw an equal strain upon each, and thereby obtain their aggregate strength. To obviate this inconvenience, cables, or such large ropes as are said to be cable-laid, are formed by the combination of smaller ropes twisted round their common axis, just as shroud-laid ropes are composed of strands twisted round their common axis. As cable-laid ropes are harder and more compact than others, this mode of forma tion is adopted for ropes to be exposed to the action of water, even though their thickness may not be very great.