Slide whistle
From Conservapedia
A slide whistle is a musical instrument resembling a tin whistle, but with movable piston which can be operated like the slide of a trombone. It produces a clear, musical whistle which varies smoothly and continuously in pitch. Today it is thought of primarily as a child's toy, or used as a comic sound effect, but it was used seriously in popular music of the 1920s and 1930s.
Paul Whiteman's band included a slide whistle performer,[1] heard notably in his hit song Whispering.
