A letter from George Rennie (son of John Rennie) enclosing a sketch he made from a bust of John Rennie (1771-1821) by Sir Francis Legatt Chantrey using a camera lucida. The letter dated 13 November 1822 is addressed to Mr. John Bain, 10 Bentinck Street, Berwick Street, Soho. William Bain was a medallist and designed a medal of John Rennie which will, almost certainly, have been based on the sketch. The text of the letter is as follows:
Royal Mint. Nov 13,
Some time ago I made the enclosed sketch from the bust with a Camera Lucida. Perhaps it may be useful in the new die you are going to engrave. I shall get the die ready as soon as possible.
PS. Please preserve it.
George Rennie wrote this letter as Surveyor of the Maltings and Clerk of the Irons (dies) at the Royal Mint, a position he was appointed to in 1818 on the recommendation of James Watt and Sir Joseph Banks (source: https://en.wikipedia.org/wiki/George_Rennie_(engineer)).
The museum collection contains a camera lucida (see: https://ice-museum-scotland.hw.ac.uk/product/1971-004/).