Mark Kinsler asks about an early French mechanical horn.  This reminds
me of the Testophone horn, which was made in France in the early 20th
century and was supplied to the wealthy 'boy racers' of the time.

The horn came in a number of sizes, with anything between four and ten
tuned horns.  Each horn was in brass with a free reed in its base.
They were positioned around a central cylinder which incorporated a
rotating hollow cylinder so arranged that as it rotated, an air port
was opened to each horn in turn.

The rotating cylinder had n increments to one revolution and one
revolution gave the full length of the tune.  This allowed a tune to be
played on the horns, one note at a time.  The hand-squeezed rubber bulb
supplied air to the selected horn and rotated the cylinder one increment
on each squeeze by means of a small air piston.

Testophones are still to be found today but are greatly treasured by
owners of early cars.  They fetch very high prices at auction.  I once
restored one for a friend who restored early cars.

Nicholas Simons, GB

 [ They should have named it "Testosteronophone"! ;-) -- Robbie