hydraulophone

Etymology
See and.

Noun

 * 1)  Any of several musical instruments that employ the movement of water rather than air.
 * 2) * 2007 May 17, "aleksios" (username), "Re: music with unconventional instruments", in and, Usenet:
 * Straying from classical music, there is Steve Mann's hydraulophone (which, even if not quite a match for a Silbermann organ, is great fun on a summer day):