When Doyle was in Vancouver and making music rolls I managed to buy
one of every Caliola roll on his list.  I visited him in North Carolina
later on; also, his wife who had a tea shop next door to Doyle's shop.

Among his many contributions to mechanical music I especially value
his pneumatic valves, of which I have used a great many.  He produced
a handy booklet of hints on using the valves in various configurations.
They are a real boon for the do-it-yourselfer.  I hope someone will
continue to make them available to the hobby.

Fritz Gellerman