Holy smoke!  Amongst the many amazing devices discussed herein, there
are two that stand out in the last MMD.

One device is the musical teapot that whistles 'Tea For Two' when it
boils.  How the heck do they do that?  About all I can envision is a
steam turbine powered miniature calliope.

The other is the piano roll changer.  A player piano is itself an
amazing device.  The fact that there are apparently automatic
roll-threading mechanisms is somewhat more awe-inspiring, especially to
someone like me who has dealt with clumsy record changers for some
time.  But an automatic roll changer?!  Yow!

The reason I'm interested in this last device is that it resembles in
function the automatic CD changers so common today.  In my "How things
work" talks and discussions I often cite inventions of the past and
relate them to devices that are familiar to my audience.  The idea,
I suppose, is to pique their curiosity and to engender some respect for
engineers and technologies of past ages.

Mark Kinsler
Lancaster, Ohio USA
http://home.earthlink.net/~mkinsler1

 [ A 3-tone chime whistle with a slowly rotating aperture plate
 [ could play the 3-note melody of "Tea for Two."
 [
 [ See "Philipps Pianella Mechanical Revolvers" at
 [ http://www.mechanicalmusicpress.com/history/pianella/wpo_idex.htm
 [ A good photo of a replica Philipps/Wurlitzer roll changer is at
 [ http://mmd.foxtail.com/Events/010630/index.html
 [ -- Robbie