MEMOIR OF DANIEL TR1WDWELL. 



37 



To fit rope-yarns for certain kinds of cordage it is necessary (hat they should 

 resist the action of water. They are for this purpose treated with tar. This had 

 usually been done by a very simple apparatus ; the yarns being drawn through an 

 ordinary kettle of hot tar, the superabundant 1ar squeezed out, and the yarn- 

 wound on a reel. In 1834, Mr. Treadwell invent* 1 "an improvement which con- 

 sists of three distinct parts: first, in the method of heating the tar; second, in rubbing 

 and untwisting the yarn for the purpose of saturating it with tar: third, in the nij>- 

 pers for pressing out the superabundant tar." The bobbins, upon which is wound 

 the white yarn, are arranged in any number at one of the ends of a long trough, 



which contains the tar, heated by steam-pipes. Above this trough is arranged a 

 frame, having on its legs plates of iron pierced with holes through which the rope- 

 yarns pass. On each of these plates are two others, one on each Bide, also pierci I 

 with holes for the yarns; these plates are fastened to rods, which are attached by 

 cranks at their upper end to a rotating bar, and also at their middle by means of 

 pins to the frame. When the cranks are turned, the plates have a rotary motion 

 around the holes in the middle plate, by which the yarn is untwisted and prepai d 

 to receive the tar; they then move on, the twist bcinu taken out as they move, and 

 pass between tw T o rollers, the upper one movable and weighted, by which the super- 

 abundant tar is squeezed out and the yarns wound on a bobbin. Some of these 

 troughs are thirty feet long, and the yarn from a hundred bobbins i- drawn through 

 the tar at one time by a capstan. They are still in use at the Charlestown Navy 

 Yard. 



The last operation in rope-making is the twisting and combining of the yarns into 

 i cord. It is necessary that the yarns should be laid side by side, and twisted 

 together in a regular spiral. This is effected by a conical piece of wood called a 



o 



qui 



o * «" » *-« «— w_ 



yarns are laid, and by 



which they are directed as they come together at the smaller end of the top. To 

 hold back the top and increase the hardness of the rope, two or more cords or " tails " 

 are attached to its sides, which the workman grasps, and, by winding them around 

 the rope already made, regulates by their friction the hardness of the twist given 



it by the twisting-wheel. The success of 



depend 



upon the judgment of the workman. For improving this process, Mr. Treadwell 

 invented the instrument which he calls an "Iron-tail," the character of the in- 

 vention being comprised in the construction and use of rubbers formed of some 

 solid body, by which they are capable of preserving their own figure, and of con- 

 straining the rope over which they pass to assume the figure defined by them. 



