Coster, John

SUBJECT AREA: Metallurgy, Mining and extraction technology

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b. c. 1647 Gloucestershire, England

d. 13 October 1718 Bristol, England

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English innovator in the mining, smelting and working of copper.

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John Coster, son of an iron-forge manager in the Forest of Dean, by the age of 38 was at Bristol, where he was "chief agent and sharer therein" in the new lead-smelting methods using coal fuel. In 1685 the work, under Sir Clement Clerke, was abandoned because of patent rights claimed by Lord Grandison, who financed of earlier attempts. Clerke's business turned to the coal-fired smelting of copper under Coster, later acknowledged as responsible for the subsequent success through using an improved reverberatory furnace which separated coal fume from the ores being smelted. The new technique, applicable also to lead and tin smelting, revitalized copper production and provided a basis for new British industry in both copper and brass manufacture during the following century. Coster went on to manage a copper-smelting works, and by the 1690s was supplying Esher copper-and brass-works in Surrey from his Redbrook, Gloucestershire, works on the River Wye. In the next decade he extended his activities to Cornish copper mining, buying ore and organizing ore sales, and supplying the four major copper and brass companies which by then had become established. He also made copper goods in additional water-powered rolling and hammer mills acquired in the Bristol area. Coster was ably assisted by three sons; of these, John and Robert were mainly active in Cornwall. In 1714 the younger John, with his father, patented an "engine for drawing water out of deep mines". The eldest son, Thomas, was more involved at Redbrook, in South Wales and the Bristol area. A few years after the death of his father, Thomas became partner in the brass company of Bristol and sold them the Redbrook site. He became Member of Parliament for Bristol and, by then the only surviving son, planned a large new smelting works at White Rock, Swansea, South Wales, before his death in 1734. Partners outside the family continued the business under a new name.

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Bibliography

1714, British patent 397, with John Coster Jr.

Further Reading

Rhys Jenkins, 1942, "Copper works at Redbrook and Bristol", Transactions of the Bristol and Gloucestershire Archaeological Society 63.

Joan Day, 1974–6, "The Costers: copper smelters and manufacturers", Transactions of the Newcomen Society 47:47–58.

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