Some years ago I 'restored' a Testophone for a friend who restores
vintage and veteran cars. This particular one had been bought by a
client of his for one of his veteran cars and was supplied in pieces
with all the reeds and horns separate from the cylinder mechanism.

They were made in different sizes ranging from having anything from
four to at least eight horns.  The rubber bulb passed air into the
centre of the rotating cylinder and ports around the circumference
allowed air to pass to any of the horns in sequence.

The cylinder was rotated in small steps, one per squeeze of the bulb,
by means of a small piston in a cylinder, and a pawl and ratchet
mechanism.  The tune was therefore created by the arrangement of the
ports around the circumference of the main cylinder reacting with the
exit ports to the horns.  This one had at least twenty steps for one
rotation of the cylinder.

Restoration was a nightmare as I had no idea of the tune and none of
the reeds was set to its original tuning, and I had no idea what the
tuning should have been.  I tried to establish some relationship
between the note's pitches by considering the relative lengths of the
horns.  Eventually I got it to play in sequence with sensible intervals
but I didn't recognise the tune.  Maybe it was some long lost French
hit from 1905?  I was never happy with the result.

Some few years ago a large Testophone and original instruction manual
were sold in a Christies South Kensington mechanical music auction.
They are very collectable and this was reflected in the price realised.

Nicholas Simons
Great Britain