James Prinsep - Career in India

Career in India

Prinsep found a position as an assay master at the Calcutta mint and reached Calcutta along with his brother Henry Thoby on 15 September 1819. Within a year at Calcutta, he was sent by his superior, the eminent orientalist Horace Hayman Wilson, to work as assay master at the Benares mint. He stayed at Benares until the closure of that mint in 1830. He then moved back to Calcutta as deputy assay master and when Wilson resigned in 1832, he was made assay master (overruling Wilson's nominee for that position, James Atkinson) at the new silver mint designed in Greek revival style by Major W. N. Forbes. He married Harriet Sophia Aubert, elder daughter of Lieutenant-Colonel Jeremiah Aubert (grandson of Alexander Aubert) of the Bengal army and his wife Hannah, at the cathedral in Calcutta on 25 April 1835. They had a daughter Eliza in 1837 who was to be the only child to survive.

His work assay master led him to conduct many scientific studies. He worked on means for measuring high temperatures in furnaces accurately. The publication of his techique in the Philosophical Transactions of the Royal Society of London in 1828 led to his election as a Fellow of the Royal Society. He suggested the possibility of visual pyrometric measurement using a calibrated series of mica plates as well as using the thermal expansion of platinum but considered that a practical approach was to use calibrated combinations of platinum, gold and silver alloys placed in a cupel or crucible and observe their melting. He also described a pyrometer that measured the expansion of a small amount of air held within a gold bulb. In 1833 he called for reforms to Indian weights and measures and advocated a uniform coinage based on the new silver rupee of the East India Company. He also devised a balance so delicate as to measure three-thousandth of a grain (≈0.19 mg).