Patented (in 1924) pneumatically-actuated slide whistle. The pitch rises and falls as the bottom slide or stopper is moved in and out. Sometimes called a lotus flute (although lotus flute refers to another style of pipe). Popular addition to jazzband-type orchestrions of the 1920s, for imitating the slide whistle which was popular in dance bands of the time.
MBSI
Musical Box Society International