HOPE-MAKING 



719 



directly above and close down to where the rope is laid at A, the insdie of which is 

 polished, and the under end is bell-mouthed ; to prevent the rope from being chafed in 

 entering it, a sufficient grip or pressure is put upon the rope by one or two levers and 

 weights, 5, 5, acting upon the press-block, so as to adjust any trifling irregularity in 

 the strand or in the laying ; the inside of which, being polished, gives smoothness, 

 and by the said levers and weights, a proper tension to the rope, as it is drawn 

 forward through the press-block. By the application of this block, ropes may be 

 made at once properly stretched, rendering them decidedly preferable and extremely 

 advantageous particularly for shipping, inclined planes, mines, &c. 



The preceding description includes the whole of Mr. Norvell's improvements ; the 

 remaining parts of the machine may be briefly described as follow : A wheel or 

 pulley, c, is fixed independently of the machine, over which the rope passes to the 

 drawing motion represented at the side ; d, d, is a grooved wheel, round which the 

 rope is passed, and pressed into the groove by means of the lever and weight e, e, 

 acting upon the binding-sheaf /, to prevent the rope from slipping. After the rope 

 leaves the said sheaf, it is coiled away at pleasure, g, g, are two change-wheels, for 

 varying the speed of the grooved wheel d, d, to answer the various sizes of ropes ; h, 

 is a spiral wheel, driven by the screw k, fixed upon the axle I ; m is a band-wheel, 

 which is driven by a belt from the shaft of the engine, or any .other communicating 

 power ; n, n, is a friction-strap and striking-clutch. The axle q is driven by two 

 change- wheels p, p ; by changing the sizes of those wheels, the different speeds ofthe 

 drum E, R, for any sizes of ropes, are at once effected. 



The additional axle s, and wheels t, t, shown in fig. 1733, are applied occasionally 



1733 



for reversing the motion of the said drums, and making what is usually termed left- 

 hand ropes; -u, figs. 1732, 1733, shows a bevelled pinion, driving the main crown- 

 wheel v, v, which wheel carries and gives motion to the drums B, R ; w, w, is a fixed 

 or sun-wheel, which gives a reverse motion to the drums, as they revolve round the 

 same, by means of the intervening wheels x, x, x, whereby the reverse or retrograd- 

 ing motion is produced, which gives to the strands the right twist. The various 

 retrograding motion or right twist for all sizes and descriptions of ropes, may be 

 obtained by changing the diameters of the pinions y, y, y, on the under ends of the 

 drum spindles ; the carriages of the intervening wheels x, x, x, being made to slide 

 round the ring z, z ; w, "w, is the framework of the machine and drawing motion ; 

 T, T, T, are the bobbins containing the yarns ; their number is varied to correspond 

 with the different sizes of the machine. 



Messrs. Chapman, of Newcastle, having observed that rope-yarn is weakened by 

 passing through the tar-kettle, that tarred cordage loses its strength progressively in 

 cold climates, and so rapidly in hot climates as to be scarcely fit for use in three 

 years, discovered that the deterioration was due to the reaction of the mucilage and 

 acid of the tar. They accordingly proposed the following means of amelioration : 



1. Boiling the tar with water, in order to remove these two soluble constituents. 



2. Concentrating the washed tar by heat, till it becomes pitchy, and then restoring 

 the plasticity which it thereby loses, by the addition of tallow, or animal or expressed 

 oils. 



The same engineers patented a method of making a belt or flat band, of two, three, 

 or more strands of shroud or hawser-laid rope, placed side by side, so as to form a 

 band of any desired 'breadth, which maybe used for hoisting the kibbles and corves in 

 mine-shafts, without any risk of its losing twist by rotation. The ropes should be 

 laid with the twist of the one straud directed to the right hand, that of the other to 

 the left, and that of the yarns the opposite way to the strands, whereby perfect 

 flatness is secured to the band. This parallel assemblage of strands has been found 

 also to be stronger than when they are all twisted into one cylinder. The patentees 

 at the same time contrived a mechanism for piercing the strands transversely, in 

 order to brace them firmly together with twine. Flat ropes are usually formed of 

 hawsers with three strands, softly laid, each containing thirty -three yarns, which with 



