The Tin Cornet Band

From the 1910 young adult novel The Emerald City of Oz by L. Frank Baum. They are a group of Winkies who play for the pleasure of their Emperor, the Tin Man. Presumably they play cornets made of tin.

That evening after dinner they were entertained by the Emperor's Tin Cornet Band, which played for them several sweet melodies. Also the Wizard did a few sleight-of-hand tricks to amuse the company; after which they all retired to their cosy tin bedrooms and slept soundly until morning.

See also The Winsome Waggish Warblers from the same novel, and The Tin Band, another of the Emperor Tin Man's musical groups, from a different novel.