Added several images to the 19th century Trombone History Timeline (2nd half). I don’t know that there’s really any overarching theme here, unless perhaps it’s humor.

c. 1855—Artist Albert Kindler includes a trombonist in his painting After the Wedding. The trombonist stands in the musicians’ boat in the background (see below detail and full image; public domain).

1881—New York: A poster for Edmond Audran’s operetta, The Mascot (La Mascottein the original), features a trombone player. The operetta plays at New York’s Bijou Theatre (see below image; public domain) (source: Library of Congress).

c. 1892—A postcard features an image of two Victorian children playing with a trombone. The trombone appears to have an slide extension handle (see below image; public domain).

1898—New York: A poster advertising a touring “Rag Time Opera,” By the Sad Sea Waves, depicts a trombonist playing with piano. The duo, according to the caption, is “Playing ‘to beat the band!’” (see below image; public domain) (source: Library of Congress).