Shortly after Maty died he fell into debt, and lost his museum position of Assistant Librarian in 1778, being replaced by Edward Whitaker Gray.
[12] Thomas Spencer Wells wrote in 1860 that Justamond had anticipated cancer cures then recently in fashion in London.
In 1775 the Philadelphia printer James Humphreys had printed translated extracts from Raynal's work as the pamphlet The Sentiments of a Foreigner, on the Disputes of Great-Britain with America.
[16] A Philosophical and Political History of the British Settlements and Trade in North America (Edinburgh, 1779) was a part of Justamond's translation.
He commented on the Ciceronian manner of two of Chesterfield's political speeches, not knowing that the author was Samuel Johnson.