double+description+method

1) Mathematics: double-description method

2) Economy: double description method

SUBJECT AREA: Land transport, Mining and extraction technology, Railways and locomotives

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The son of a "coal viewer", Curr was brought up in the West Durham colliery district. In 1777 he went to the Duke of Norfolk's collieries at Sheffield, where in 1880 he was appointed Superintendent. There coal was conveyed underground in baskets on sledges: Curr replaced the wicker sledges with wheeled corves, i.e. small four-wheeled wooden wagons, running on "rail-roads" with cast-iron rails and hauled from the coal-face to the shaft bottom by horses. The rails employed hitherto had usually consisted of plates of iron, the flange being on the wheels of the wagon. Curr's new design involved flanges on the rails which guided the vehicles, the wheels of which were unflanged and could run on any hard surface. He appears to have left no precise record of the date that he did this, and surviving records have been interpreted as implying various dates between 1776 and 1787. In 1787 John Buddle paid tribute to the efficiency of the rails of Curr's type, which were first used for surface transport by Joseph Butler in 1788 at his iron furnace at Wingerworth near Chesterfield: their use was then promoted widely by Benjamin Outram, and they were adopted in many other English mines. They proved serviceable until the advent of locomotives demanded different rails.

In 1788 Curr also developed a system for drawing a full corve up a mine shaft while lowering an empty one, with guides to separate them. At the surface the corves were automatically emptied by tipplers. Four years later he was awarded a patent for using double ropes for lifting heavier loads. As the weight of the rope itself became a considerable problem with the increasing depth of the shafts, Curr invented the flat hemp rope, patented in 1798, which consisted of several small round ropes stitched together and lapped upon itself in winding. It acted as a counterbalance and led to a reduction in the time and cost of hoisting: at the beginning of a run the loaded rope began to coil upon a small diameter, gradually increasing, while the unloaded rope began to coil off a large diameter, gradually decreasing.

Curr's book The Coal Viewer (1797) is the earliest-known engineering work on railway track and it also contains the most elaborate description of a Newcomen pumping engine, at the highest state of its development. He became an acknowledged expert on construction of Newcomen-type atmospheric engines, and in 1792 he established a foundry to make parts for railways and engines.

Because of the poor financial results of the Duke of Norfolk's collieries at the end of the century, Curr was dismissed in 1801 despite numerous inventions and improvements which he had introduced. After his dismissal, six more of his patents were concerned with rope-making: the one he gained in 1813 referred to the application of flat ropes to horse-gins and perpendicular drum-shafts of steam engines. Curr also introduced the use of inclined planes, where a descending train of full corves pulled up an empty one, and he was one of the pioneers employing fixed steam engines for hauling. He may have resided in France for some time before his death.

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WK / PJGR

SUBJECT AREA: Textiles

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John Kay was the youngest of five sons of a yeoman farmer of Walmersley, near Bury, Lancashire, who died before his birth. John was apprenticed to a reedmaker, and just before he was 21 he married a daughter of John Hall of Bury and carried on his trade in that town until 1733. It is possible that his first patent, taken out in 1730, was connected with this business because it was for an engine that made mohair thread for tailors and twisted and dressed thread; such thread could have been used to bind up the reeds used in looms. He also improved the reeds by making them from metal instead of cane strips so they lasted much longer and could be made to be much finer. His next patent in 1733, was a double one. One part of it was for a batting machine to remove dust from wool by beating it with sticks, but the patent is better known for its description of the flying shuttle. Kay placed boxes to receive the shuttle at either end of the reed or sley. Across the open top of these boxes was a metal rod along which a picking peg could slide and drive the shuttle out across the loom. The pegs at each end were connected by strings to a stick that was held in the right hand of the weaver and which jerked the shuttle out of the box. The shuttle had wheels to make it "fly" across the warp more easily, and ran on a shuttle race to support and guide it. Not only was weaving speeded up, but the weaver could produce broader cloth without any aid from a second person. This invention was later adapted for the power loom. Kay moved to Colchester and entered into partnership with a baymaker named Solomon Smith and a year later was joined by William Carter of Ballingdon, Essex. His shuttle was received with considerable hostility in both Lancashire and Essex, but it was probably more his charge of 15 shillings a year for its use that roused the antagonism. From 1737 he was much involved with lawsuits to try and protect his patent, particularly the part that specified the method of winding the thread onto a fixed bobbin in the shuttle. In 1738 Kay patented a windmill for working pumps and an improved chain pump, but neither of these seems to have been successful. In 1745, with Joseph Stell of Keighley, he patented a narrow fabric loom that could be worked by power; this type may have been employed by Gartside in Manchester soon afterwards. It was probably through failure to protect his patent rights that Kay moved to France, where he arrived penniless in 1747. He went to the Dutch firm of Daniel Scalongne, woollen manufacturers, in Abbeville. The company helped him to apply for a French patent for his shuttle, but Kay wanted the exorbitant sum of £10,000. There was much discussion and eventually Kay set up a workshop in Paris, where he received a pension of 2,500 livres. However, he was to face the same problems as in England with weavers copying his shuttle without permission. In 1754 he produced two machines for making card clothing: one pierced holes in the leather, while the other cut and sharpened the wires. These were later improved by his son, Robert Kay. Kay returned to England briefly, but was back in France in 1758. He was involved with machines to card both cotton and wool and tried again to obtain support from the French Government. He was still involved with developing textile machines in 1779, when he was 75, but he must have died soon afterwards. As an inventor Kay was a genius of the first rank, but he was vain, obstinate and suspicious and was destitute of business qualities.

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