Just added the following two images and their captions to the 19th Century Timeline (first half and second half). The first one, Musique d’Amateurs, has also been added to the post Serpent & Ophicleide: History and Images. The second one, The Elections in England, will also be added to the article Backward Advances: Rear-Facing Trombones Throughout History.
1840—Epinal, France: An engraving entitled Musique d’Amateurs, published by Pellerin, features 3 trombones among 27 figures with various musical instruments. One of the trombones is a buccin, or dragon-bell instrument (see below image; click picture for larger version; public domain).
1852—Paris, France: A print by Janet-Lange entitled The Elections in England includes a rear-facing trombone (see detail below; public domain) (L’Illustration, July 17, 1852, p. 33).