ROPE-MAKING

The fibres of hemp which compose a rope, seldom exceed in length three feet and a half, at an average. They must, therefore, be twined together so as to unite them into one; and this union is effected by the mutual cir cum torsion of the two fibres. If the compre ion thereby produced be too great, the strength of the fibres at the points where they join will be diminished; so that it becomes a matter of great consequence to give them only such a degree of twist as is e ential to their union. The first part of the proce of rope-making by hand, is that of spinning the yarns or threads, which is done in a manner analogous to that of ordinary spinning. The spinner carries a bundle of dre ed hemp round his waist; the two ends of the bundle being a embled in front. Having drawn out a proper number of fibres with his hand, he twists them with his fingers, and fixing this twisted part to the hook of a whirl, which is driven by a wheel put in motion by an a istant, he walks backwards down the rope walk, the twisted part always serving to draw out more fibres from the bundle round his waist, as in the flax-spinning wheel. The spinner takes care that these fibres are equably supplied, and that they always enter the twisted parts by their ends, and never by their middle. As soon as he has reached the termination of the walk, a second spinner takes the yarn off the whirl, and gives it to another person to put upon a reel, while he himself attaches his own hemp to the whirl hook, and proceeds down the walk. When the person at the reel begins to turn, the first spinner, who has completed his yarn, holds it firmly at the end, and advances slowly up the walk, while the reel is turning, keeping it equally tight all the way, till he reaches the reel, where he waits till the second spinner takes his yarn off the whirl hook, and joins it to the end of that of the first spinner, in order that it may follow it on the reel. The next part of the proce previous to tarring, is that of warping the yarns, or stretching them all to one length, which is about 200 fathoms in full-length rope-grounds, and also in putting a slight turn or twist into them. The third proce in rope-making, is the tarring of the yarn. Sometimes the yarns are made to wind off one reel, and, having pa ed through a ve el of hot tar, are wound upon another, the superfluous tar being removed by causing the yarn to pa through a hole surrounded with spongy oakum; but the ordinary method is to tar it in skains or hanks, which are drawn by a capstan with a uniform motion through the tar-kettle. In this proce , great care must be taken that the tar is boiling neither too fast nor too slow. Yarn for cables requires more tar than for hawser-laid ropes; and for standing and running rigging, it requires to be merely well covered. Tarred cordage has been found to be weaker than what is untarred, when it is new; but the tarred rope is not so easily injured by immersion in water. The last part of the proce of rope-making, is to lay the cordage. For this purpose two or more yarns are attached at one end to a hook. The hook is then turned the contrary way from the twist of the individual yarn, and thus forms what is called a strand. Three strands, sometimes four, besides a central one, are then stretched at length, and attached at one end to three contiguous but separate hooks, but at the other end to a single hook; and the proce of combining them together, which is effected by turning the single book in a direction contrary to that of the other three, consists in so regulating the progre of the twists of the strands round their common axis, that the three strands receive separately at their opposite ends just as much twist as is taken out of them by their twisting the contrary way, in the proce of combination. Large ropes are distinguished into two main cla es, the cable-laid and hawser-laid . The former are composed of nine strands, namely, three great strands, each of these consisting of three smaller secondary strands, which are individually formed with an equal number of primitive yarns. A cable-laid rope eight inches in circumference, is made up of 333 yarns or threads, equally divided among the nine secondary strands. A hawser-laid rope consists of only three strands, each composed of a number of primitive yarns, proportioned to the size of the rope; for example, if it be eight inches in circumference, it may have 414 yarns, equally divided among three strands. Thirty fathoms of yarn are reckoned equivalent in length to eighteen fathoms of rope cable-laid, and to twenty fathoms hawser-laid. Ropes of from one inch to two inches and a half in circumference are usually hawser-laid; of from three to ten inches, are either hawser or cable laid; but when more than ten inches, they are always cable-laid. Every hand-spinner in the dock-yard is required to spin, out of the best hemp, six threads, each 160 fathoms long, for a quarter of a day’s work. A hawl of yarn, in the warping proce , contains 336 threads. The following are Captain Huddart’s improved principles of the rope manufacture :— 1. To keep the yarns separate from each other, and to draw them from bobbins revolving upon skewers, so as to maintain the twist while the strand or primary cord is forming. 2. To pa them through a register, which divides them by circular shells of holes; the number in each concave shell being conformable to the distance from the centre of the strand, and the angle which the yarns make with a line parallel to it, and which gives them a proper position to enter. 3. To employ a tube for compre ing the strand, and preserving the cylindrical figure of its surface. 4. To use a gauge for determining the angle which the yarns in the outside shell make with a line parallel to the centre of the strand, when registering; because according to the angle made by the yarns in this shell, the relative lengths of all the yarns in the strand will be determined. 5. To harden up the strand, and thereby increase the angle in the outside shell; which compensates for the stretching of the yarns, and the compre ion of the strands. A great many patents have been obtained, and worked with various degrees of succe , for making ropes. Me rs. Cartwright, Fother gill, Curr, Chapman, Balfour, and Huddart, have been the most conspicuous inventors in this country; but the limits of this work preclude us doing justice to their respective merits. All improvements in the manufacture of cordage at present in use, either in her Majesty’s yards or in private rope-grounds, owe their superiority over the old method of making cordage to Captain Huddart’s invention of the register plate and tube. Mr. Balfour took out a patent for the manufacture of cordage about a month before Captain Huddart; but the formation of his strand was to be accomplished by what he called a top minor, (in the form of a common top, with pins to divide the yarns,) which upon trial could not make cordage so good as by the common mode. On seeing Captain Huddart’s specification, Mr. Balfour, five years after, procured another patent, in which he included a plate and tube, but which was not sufficiently correct, and experience in the navy proved the insufficiency of the cordage. Captain Huddart’s plate and tube were then adopted in the king’s yards, and he gave his a istance for the purpose. Captain Huddart then invented and took a patent for a machine, which by registering the strand at a short length from the tube, and winding it up as made, preserved an uniformity of twist, or angle of formation, from end to end of the rope, which cannot be accomplished by the method of forming the strands down the ground, where the twist is communicated from one end to the other of an elastic body upwards of 300 yards in length. This registering-machine was constructed with such correctne , that when some were afterwards required, no alteration could be made with advantage by the most skilful and scientific mechanic of that day, Mr. Rennie. Thus the cold register was carried to the greatest perfection. A number of yarns cannot be put together in a cold state, without considerable vacancies, into which water may gain admi ion; Captain Huddart, therefore, formed the yarns into a strand immediately as they came from the tar-kettle, which he was enabled to do by his registering-machine, and the result was most satisfactory. This combination of yarns was found by experiment to be 14 per cent. stronger than the cold register; it constituted a body of hemp and tar impervious to water, and had great advantage over any other cordage, particularly for shrouds, as after they were settled on the mast-head, and properly set up, they had scarcely any tendency to stretch, effectually secured the mast, and enabled the ship to carry the greatest pre of sail. In order more effectually to obtain correctne in the formation of cables and large cordage, Captain Huddart constructed a laying-machine, which has carried his inventions in rope-making to the greatest perfection, and which, founded on true mathematical principles, and the most laborious calculations, is one of the noblest monuments of mechanical ability since the improvement of the steam-engine by Mr. Watt. By this machine, the strands receive that degree of twist only which is nece ary, and are laid at any angle with the greatest regularity; the pre ure is regulated to give the required elasticity, and all parts of the rope are made to bear equally. In no one instance has a rope or cable thus formed, been found defective in the lay, or stiff, or difficult to coil. Such a revolution in the manufacture of cordage could not be accomplished without great expense, as the works at Lime house fully testify; and considerable opposition nece arily arose. Captain Huddart’s first invention was, however, generally adopted, as soon as the patent expired; and experience has established the great importance of his subsequent improvements. His cordage has been supplied in large quantities to her Majesty’s navy, and has received the most satisfactory reports. The following description of one of the best modern machines for making ropes on Captain Huddart’s plan, will gratify the intelligent reader. IMG:4147767755307473660_illo1071.png:Rope making machine Fig. 942 enlarged (100 kB) Fig. 942. exhibits a side elevation of the tackle-board and bobbin-frame at the head of the ropery, and also of the carriage or rope-machine in the act of hauling out and twisting the strands. IMG:4147767755307473660_illo1072.png:Rpoe making machine Fig. 943. is a front elevation of the carriage. Fig. 944. is a yarn-guide, or board, or plate, with perforated holes for the yarns to pa through before entering the nipper. Figs. 945. and 946. are side and front views of the nipper for pre ing the rope-yarns. a is the frame for containing the yarn bobbins. The yarns are brought from the frame, and pa through a yarn-guide at b . c is a small roller, under which the rope-yarns pa ; they are then brought over the reel d , and through another yarn-guide e , after which they enter the nippers at v , and are drawn out and formed into strands by the carriage. The roller and reel may be made to traverse up and down, so as to regulate the motion of the yarns. The carriage runs on a railway. f , f , is the frame of the carriage; g , g , are the small wheels on which it is supported; k , k , is an endle rope, reaching from the head to the bottom of the railway, and is driven by a steam-engine; m , m , is a wheel with gubs at the back of it, over which the endle rope pa es, and gives motion to the machinery of the carriage. n , is the ground rope for taking out the carriage, as will be afterwards described. On the shaft of m , m , are two bevel wheels 3, 3, with a shifting catch between them; these bevel wheels are loose upon the shaft, but when the catch is put into either of them, this last then keeps motion with the shaft, while the other runs loose. One of these wheels serves to communicate the twist to the strand in drawing out; the other gives the opposite or after turn to the rope in closing. 4, 4, is a lever for shifting the catch accordingly. 5, is a third bevel wheel, which receives its motion from either of the other two, and communicates the same to the two spur wheels 6, 6, by means of the shaft x . These can be shifted at pleasure; so that by applying wheels of a greater or le number of teeth above and beneath, the twist given to the strands can be increased or diminished accordingly. The upper of these two communicates motion, by means of the shaft o , to another spur wheel 8, which working in the three pinions above, 9, 9, gives the twist to the strand hooks. The carriage is drawn out in the following manner. On the end of the shaft of m , m , is the pinion 3, which, working in the large wheel R , gives motion to the ground-rope shaft upon its axis. In the centre of this shaft is a curved pulley or drum t , round which the ground rope takes one turn. This rope is fixed at the head and foot of the ropery; so that when the machinery of the carriage is set a-going by the endle rope k , k , and gives motion to the ground-rope shaft, as above described, the carriage will nece arily move along the railway; and the speed may be regulated either by the diameter of the circle formed by the gubs on the wheel m , m , or by the number of teeth in the pinion 3. At T , is a small roller, merely for preventing the ground rope from coming up among the machinery. At the head of the railway, and under the tackle-board, is a wheel and pinion Z , with a crank for tightening the ground rope. The fixed machinery at the head, for hardening or tempering the strands, is similar to that on the carriage, with the exception of the ground-rope geer, which is unnece ary. The motion is communicated by another endle rope, (or short band, as it is called, to distinguish it from the other,) which pa es over gubs at the back of the wheel 1, 1. When the strands are drawn out by the carriage to the requisite length, the spur wheels 3, R , are put out of geer. The strands are cut at the tackle-board, and fixed to the hooks 1, 1, 1; after which they are hardened or tempered, being twisted at both ends. When this operation is finished, three strands are united on the large hook h , the top put in, and the rope finished in the usual way. In preparing the hemp for spinning an ordinary thread or rope-yarn, it is only heckled over a large keg or clearer, until the fibres are straightened and separated, so as to run freely in the spinning. In this case, the hemp is not stript of the tow, or cropt, unle it is designed to spin beneath the usual grist, which is about 20 yarns for the strand of a three-inch strap-laid rope. The spinning is still performed by hand, being found not only to be more economical, but also to make a smoother thread, than has yet been effected by machinery. Various ways have been tried for preparing the yarns for tarring. That which seems now to be most generally in use, is, to warp the yarns upon the stretch as they are spun. This is accomplished by having a wheel at the foot, as well as the head of the walk, so that the men are able to spin both up and down, and also to splice their threads at both ends. By this means, they are formed into a haul, resembling the warp of a common web, and a little turn is hove into the haul, to preserve it from getting foul in the tarring. The advantages of warping from the spinners, as above, instead of winding on winches, as formerly, are, 1st, the saving of this last operation altogether; 2dly, the complete check which the foreman has of the quantity of yarn spun in the day; 3dly, that the quality of the work can be subjected to the minutest inspection at any time. In tarring the yarn, it is found favourable to the fairne of the strip, to allow it to pa around or under a reel or roller in the bottom of the kettle while boiling, instead of coiling the yarn in by hand. The tar is then pre ed from the yarn, by means of a sliding nipper, with a lever over the upper part, and to the end of which the nece ary weight is suspended. The usual proportion of tar in ordinary ropes, is something le than a fifth. In large strap-laid ropes, which are nece arily subjected to a greater pre in the laying of them, the quantity of tar can scarcely exceed a sixth, without injuring the appearance of the rope when laid. For a long period, the manner of laying the yarns into ropes, was by stretching the haul on the rope-ground, parting the number of yarns required for each strand, and twisting the strands at both ends, by means of hand-hooks, or cranks. It will be obvious that this method, especially in ropes of any considerable size, is attended with serious disadvantages. The strand must always be very uneven; but the principal disadvantage, and that which gave rise to the many attempts at improvement, was, that the yarns being all of the same length before being twisted, it followed, when the rope was finished, that while those which occupied the circumference of the strand were perfectly tight, the centre yarns, on the other hand, as they were now greatly slackened by the operation of hardening or twisting the strands, actually would bear little or no part of the strain when the rope was stretched, until the former gave way. The method displayed in the preceding figures and description, is among the latest and most improved; Every yarn is given out from the bobbin frame as it is required in twisting the rope; and the twist communicated in the out-going of the carriage, can be increased or diminished at pleasure. In order to obtain a smooth and well-filled strand, it is nece ary also, in pa ing the yarns through the upper board, to proportion the number of centre to that of outside yarns. In ordinary sized ropes, the strand seems to have the fairest appearance, when the outside yarns form from 2 ⁄ 3 ds to 3 ⁄ 4 ths of the whole quantity, in the portion of twist given by the carriage in drawing out and forming the strands. IMG:4147767755307473660_illo1073.png:Cable making machine In laying cables, torsion must be given both behind and before the laying top. Figs. 947 , 948 , 949. represent the powerful patent apparatus employed for this purpose. A , is a strong upright iron pillar, supported upon the great horizontal beam N , N , and bearing at its upper end the three-grooved laying top M . H , H , are two of the three great bobbins or reels round which the three secondary strands or small hawsers are wound. These are drawn up by the rotation of the three feeding rollers I , I , I , thence proceed over the three guide pulleys K , K , K , towards the laying top M , and finally pa through the tube O , to be wound upon the cable-reel D . The frames of the three bobbins H , H , H , do not revolve about the fast pillar A , as a common axis; but each bobbin revolves round its own shaft Q , which is steadied by a bracing collet at N , and a conical step at its bottom. The three bobbins are placed at an angle of 120 degrees apart, and each receives a rotatory motion upon its axis from the toothed spur wheel B , which is driven by the common central spur wheel C . Thus each of the three secondary cords has a proper degree of twist put into it in one direction, while the cable is laid, by getting a suitable degree of twist in an opposite direction, from the revolution of the frame or cage G , G , round two pivots, the one under the pulley E , and the other over O . The reel D has thus, like the bobbins H , H , two movements; that in common with its E , upon one of its ends, and the pulley E ′ above its centre of rotation. The pulley E is driven by the bevel mill-geering P , P , P , as also the under spur wheel C . L , in fig. 949. , is the place of the ring L , fig. 947. , which bears the three guide pulleys K , K , K . Fig. 948. is an end view of the bobbin H , to show the worm or endle screw J , of fig. 949. , working into the two snail-toothed wheels, upon the ends of the two feed-rollers I , I , which serve to turn them. The upright shafts of J , J , receive their motion from pulleys and cords near their bottom. Instead of these pulleys, and the others E , E ′, bevel-wheel geering has been substituted with advantage, not being liable to slip, like the pulley-band mechanism. The axis of the great reel is made twice the length of the bobbin D , in order to allow of the latter moving from right to left, and back again alternately, in winding on the cable with uniformity as it is laid. The traverse mechanism of this part is, for the sake of perspicuity, suppre ed in the figure. Mr. William Norvell, of Newcastle, obtained a patent in May, 1833, for an improvement adapted to the ordinary machines employed for twisting hempen yarns into strands, affording, it is said, a simpler and more eligible mode of accomplishing that object, and also of laying the strands together, than has been hitherto effected by machinery. The yarns spun from the fibres of hemp, are wound upon bobbins, and these bobbins are mounted upon axles, and hung in the frame of the machine, as shown in the elevation, fig. 950. , from which bobbins the several ends of yarn are pa ed upwards through slanting tubes; by the rotation of which tubes, and of the carriages in which the bobbins are suspended, the yarns become twisted into strands, and also the strands are laid so as to form ropes. IMG:4147767755307473660_illo1074.png:Hemp spinner Fig. 950 enlarged (152 kB) His improvements consist, first, in the application of three or more tubes, two of which are shown in fig. 950 , placed in inclined positions, so as to receive the strands immediately above the pre -block a , a , and nearly in a line with A , the point of closing or laying the rope. B 1 , and B 3 , are opposite side views; B 2 , an edge view; and B , a side section of the same. He does not claim any exclusive right of patent for the tubes themselves, but only for their form and angular position. Secondly, in attaching two common flat sheaves, or pulleys, C , C , fig. 950. , to each of the said tubes, nearly round which each strand is lapped or coiled, to prevent it from slipping, as shown in the section B 1 . The said sheaves or pulleys are connected by a crown or centre wheel D , loose upon b , b , the main or upright axle; E , E , is a smaller wheel upon each tube, working into the said crown or centre wheel, and fixed upon the loose box I , on each of the tubes. F , F , is a toothed or spur wheel, fixed also upon each of the loose boxes I , and working into a smaller wheel G , upon the axis 2, of each tube; H , is a bevel wheel fixed upon the same axis with G , and working into another bevel wheel J , fixed upon the cro axle 3, of each tube; K , is a spur wheel attached to the same axis with J , at the opposite end, and working into L , another spur wheel of the same size upon each of the tubes. By wheels thus arranged and connected with the sheaves or pulleys, as above described, a perfectly equal strain or tension is put upon each strand as drawn forward over the pulley C . Thirdly, the invention consists in the introduction of change wheels M , M , M , M , fig. 950. , for putting the forehard or proper twist into each strand before the rope is laid; this is effected by small spindles on axles 4, 4, placed parallel with the line of each tube B . Upon the lower end of each spindle the bevel wheels N , N , are attached, and driven by other bevel wheels O , O , fixed immediately above each pre -block a , a . On the top end of each spindle or axle 4, 4, is attached one of the change wheels, working into the other change wheel fixed upon the bottom end of each of the tubes, whereby the forehard or proper twist in the strands for all sizes of ropes, is at once attained, by simply changing the sizes of those two last described wheels, which can be very readily effected, from the manner in which they are attached to the tubes B , B , and 4, 4. From the angular position of the tubes towards the centre, the strands are nearly in contact at their upper ends, where the rope is laid, immediately below which the forehard or proper twist is given to the strands. Fourthly, in the application of a pre -block P , of metal, in two parts, placed directly above and close down to where the rope is laid at A , the inside 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 pre ure is put upon the rope by one or two levers and weights 5, 5, acting upon the pre -block, so as to adjust any trifling irregularity in the strand or in the laying; the inside of which being polished, gives smoothne , and by the said levers and weights, a proper tension to the rope, as it is drawn forward through the pre -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, . The preceding description includes the whole of Mr. Norvell’s improvements; the remaining parts of the machine being similar to those now in use, may be briefly described as follows:—A wheel or pulley c , is fixed independently of the machine, over which the rope pa es to the drawing motion represented at the side; d , d , is a grooved wheel, round which the rope is pa ed, and pre ed into the groove by means of the lever and weight e , e , acting upon the binding sheaf f , to prevent the rope from slipping. After the rope leaves the said sheave, 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 l ; 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 of the drum R , R , for any sizes of ropes, are at once effected. IMG:4147767755307473660_illo1075.png:Gear wheels and axle The additional axle s , and wheels t , t , shown in fig. 951. , are applied occasionally for reversing the motion of the said drums, and making what is usually termed left-hand ropes; u , figs. 950. and 951. , show a bevelled pinion, driving the main crown wheel v , v , which wheel carries and gives motion to the drums R , 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 retrograding motion is produced, and which gives to the strands the right twist. The various retrograding motions, or right twists 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 machines. The machine here described, in elevation and plan, is calculated to make ropes from three to seven and one-half inches in circumference, and to an indefinite length. Me rs. Chapman of Newcastle, to whom the art of rope-making is deeply indebted, having observed that rope yarn is considerably weakened by pa ing through the tar-kettle, that tarred cordage loses its strength progre ively 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 it 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 expre ed oils. In 1807, the same able engineers obtained a patent for 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 may be 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 strand 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 flatne is secured to the band. This parallel a emblage 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 33 yarns, which with four ropes, compose a cordage four and a half inches broad, and an inch and a quarter thick, being the ordinary dimensions of the grooves in the whim-pulleys round which they pa . Relative Strength of Cordage , shroud laid. | Size. | Warm Register. | Cold Register. | Common Staple. | | Tons. | Cwt. | Qrs. | Lbs. | Tons. | Cwt. | Qrs. | Lbs. | Tons. | Cwt. | Qrs. | Lbs. | | 3 | | inches bore | 3 | 17 | — | 16 | 3 | 5 | 3 | 16 | 2 | 9 | 1 | 24 | | 3 | 1⁄2 | — | 5 | 5 | — | — | 4 | 9 | 2 | 21 | 3 | 6 | 1 | 27 | | 4 | | — | 6 | 17 | — | 16 | 5 | 17 | — | 4 | 4 | 5 | 3 | 7 | | 4 | 1⁄2 | — | 8 | 13 | 2 | 8 | 7 | 5 | 3 | 1 | 5 | 1 | 2 | 6 | | 5 | | — | 10 | 14 | 1 | 4 | 9 | 3 | — | 4 | 6 | 9 | 2 | 8 | | 5 | 1⁄2 | — | 12 | 19 | 2 | 4 | 11 | 1 | 1 | 25 | 7 | 12 | — | 22 | | 6 | | — | 14 | 15 | 2 | 24 | 13 | 3 | 2 | 8 | 8 | 17 | 1 | 20 | | 6 | 1⁄2 | — | 18 | 2 | — | 10 | 15 | 9 | 1 | 9 | 9 | 16 | 3 | 14 | | 7 | | — | 21 | — | — | — | 17 | 18 | 3 | 8 | 11 | 4 | 1 | 21 | | 7 | 1⁄2 | — | 24 | 2 | — | 16 | 20 | 11 | 3 | 9 | 12 | 8 | 3 | 6 | | 8 | | — | 27 | 8 | 1 | 26 | 23 | 8 | 2 | 8 | 13 | 2 | 3 | 12 | The above statement is the result of several hundred experiments.