Slide trumpet. The instrument is wound into a single coil with ball (knop). Slide with integral spring. It has three crooks for D, D-flat and C. Its angled shank is for F (the shank does not match the crooks). The mouthpiece associated with this instrument is not useable (the mouthpiece shank is too narrow for the crooks). The mouthpiece cup is extremely shallow and its diameter very small - atypical for a slide trumpet. Marked: DISTIN/Boosey & Co./Makers/295 Regent St./London /3 2 9 7 0.
Although the valve was patented in 1817, the slide trumpet remained popular in Britain throughout much of the 19th century largely because it was the instrument used and promoted by the father and son trumpet virtuosos Thomas Harper senior and Junior.