Bb Circular Cornet by Isaac Fiske, 1855

Isaac Fiske is widely thought of as maker of the finest quality brass instruments in the US in the mid-19th century.  He is best known today for his pushrod actuated rotary valves that he called "key pistons" which he patented in 1866 and applied to all sizes of his instruments.  This circular Bb cornet is quite rare today, but at the time was a popular form.  The original ambrotype below was taken in the 1850s
and shows a musician holding a Fiske Bb circular cornet and a Graves 4 valve Bb bass in bell over the shoulder form but with a mouthpipe for playing the instrument upright.  Most Fiske instruments existing today are of German silver making this all brass example even more rare.  For more Fiske history see Robert E. Eliason's Early American Brass Makers.  The rotary valves with top action levers are .433" bore and the bell diameter is 5".  The mouthpipe shank and mouthpiece are reproductions.  It had been badly restored many years ago, requiring much careful work to bring it back to its original appearance.