He was employed by the prominent
English manufacturer and business man,
Matthew Boulton (1728 - 1809) to improve Boulton's coin and medal quality.[1] However, he worked there for just two years.[2] In 1789, Droz devised a collar used to engrave the sides of coins and ensure a circular shape, and though it was unsuitable for large numbers of coins, it remained in use at the
Soho Mint.[3]
^Flynn, Brendan (2014). RBSA: A Place for Art: The story of the Royal Birmingham Society of Artists. Liverpool: Callprint. p. 52.
^Dick, Malcolm; Quickenden, Kenneth; Baggott, Sally (2013). Matthew Boulton: Enterprising Industrialist of the Enlightenment. p. 134.
ISBN978-1-4094-2218-1.