Harris was born at Talgarth in Breconshire in 1702, and died at the Tower of London on 26 September 1764. As a Young man he worked as a blacksmith, but by 1728 he was living in London. Clearly well educated, he contributed a number of papers on astronomy and magnetism to Philosphical Transactions, and wrote later works on optics and mathematics. He probably joined the Royal Mint some time in the 1730s, and in 1748 he was appointed assay master at the Mint, a post he held until his death.
From The Biographical Dictionary of British Economists in Oxford Reference.