Australian Dictionary of Biography

Francis Bowyer Miller (1828-1887), assayer, was born on 18 December 1828 at Edgbaston, Warwickshire, England, youngest son of William Miller, brewer, and his wife Frances Bowyer, née Vaux, a writer of children's books. Both parents were Quakers, and the Miller and Vaux families were active in agitation against the slave trade. Francis was educated at King Edward's Grammar School, Birmingham, and King's College, London. In 1849 he joined a British Admiralty expedition to the Bight of Benin, Africa, to see if lagoons there could be used by British gunboats in the suppression of the slave trade. Returning to England about 1850, he worked with a mining company in Cornwall for twelve months then became an assistant to his brother William, professor of chemistry at King's College and non-resident assayer to the Royal Mint and the Bank of England.

In November 1853 Francis Miller and W. S. Jevons were appointed to the newly established Sydney branch of the Royal Mint, partly on William Miller's recommendation. Offered a retainer of £100 per annum, they were expected to establish their own assay offices and to undertake work for private banks and individuals as well as for the mint on piece rates. By the time the mint opened in May 1855, however, he and Jevons had become full-time public servants with no need to take private work. On 11 January 1854 in the Parish Church of St Clement Danes, Westminster, Miller had married Alicia, only daughter of Maurice Fitzgerald O'Connell, R.N. Two months later the Millers sailed with their servant for Sydney in the Granite City. They were to have four children.

On arrival in Sydney, Miller set up an assay office in Bligh Street. In November 1859 he became a member of the Philosophical (later Royal) Society of New South Wales, before which, in July 1860, he read a paper on the detection of spurious gold, concerned in particular with a species of fake gold 'nuggets' that had deceived many Sydney storekeepers. Rachel Henning, to whom he showed a sample 'nugget' at Bathurst in July 1861, found him to be 'rather a clever, agreeable man'.

Miller's crowning scientific achievement was his development of a process of refining and toughening gold by means of chlorine gas. He patented this process in London in June 1867 and registered it as an invention before the New South Wales Legislative Assembly in November. Twelve months later his paper describing the process was read before the Chemical Society, London, and by December 1869, when Miller read another paper on the subject before the Royal Society of New South Wales, his method had been successfully put into operation at the Sydney Mint and by the Bank of New Zealand at Auckland, New Zealand.

In 1870 Miller was transferred to the new Melbourne branch of the Royal Mint, and was paid £2000 for the sole Victorian rights to the gold-refining process. He sold the 'remarkably handsome Gothic villa and grounds' that he had built on the waterfront at Double Bay and relocated his family to the Melbourne suburb of Kew. By then Miller's method had been introduced into mints in England, the United States of America and Norway and he had travelled to England and the U.S.A. to advise on the process.

Superintendent of the bullion office at the Melbourne Mint from 1877, in 1884 he was briefly acting deputy master. Chronic Bright's disease forced him to take sick leave from June 1887 and he died in his home at Kew on 17 September 1887, survived by his wife, two sons and one daughter. He was buried with Anglican rites in Boroondara cemetery. At the time of his death he was a member of the Philosophical Society of Philadelphia, a fellow of the Chemical Society of London and of the Institute of Chemistry of Great Britain and a corresponding member of the Royal Society of New South Wales. In 2005 the Miller process was still used worldwide to treat molten gold.