Johnson, Percival Norton

SUBJECT AREA: Metallurgy

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b. 29 September 1792 London, England

d. 1 June 1866 Stoke Fleming, Devon, England

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English chemist, assayer, mining engineer and founder of the firm Johnson Matthey.

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He was the son of John Johnson, then sole Commercial Assayer in London, from whom he inherited his aptitude for chemistry and metallurgy. At the age of 14 he was apprenticed to his father by the Worshipful Company of Goldsmiths. Ore samples then being analysed in Johnson's office introduced him to the new metal platinum, and resulted in a paper to Philosophical Magazine in 1812. Johnson established himself as a "practical mineralogist" in Maiden Lane, London, in 1818 and in Hatton Garden after 1822. He was greatly assisted by a fellow metallurgist, Thomas Cock (1787–1842), who developed the platinum fabrication and pigment sides of die business. In 1827 Johnson was consulted by the Russian government about the exploitation of the rich platinum deposits that had been discovered in the Urals in 1819. Between 1829 and 1832 Johnson became the first in England to manufacture nickel, extracted from nickel-bearing material imported from Germany at his plant at Bow Common on the Regent's Canal. In 1832 he began to réfine gold imported from the Imperial Brazilian Association by a process which separated without loss the metals silver, platinum, palladium, rhodium and iridium. This profitable activity continued until the Brazilian company was wound up in 1852. Since 1824, Johnson had been named "assay master" by a number of mining companies. From 1843 until the mid-1850s he had a considerable mining interest in the West Country. Meanwhile, the Hatton Garden establishment continued to prosper. In 1839 he was joined by George Matthey, who particularly fostered the Russian platinum business, and in 1851 he was taken unto partnership and the firm became the celebrated Johnson Matthey. In the following year the firm was officially recognized as one of the four Assayers to the Bank of England appointed to handle the flood of gold dust then arriving in England from the Australian gold fields. Soon after, however, ill health compelled him to retire to his Devon country house.

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Principal Honours and Distinctions

FRS 1846.

Bibliography

1812, "Experiments which prove platina, when combined with gold and silver, to be soluble in nitric acid", Philosophical Magazine (1st series) 40(171):3–4.

Further Reading

D.McDonald, 1951, Percival Norton Johnson, London: Johnson Matthey (includes lists of his publications and his honours and awards).

——1964, The Johnsons of Morden Lane, London: Martins.

——1960, A History of Platinum, London: Johnson Matthey.

ASD