This motor is doing two basic jobs : The first one is to operate a small bellows which supplies air, via a wind chest, to a whistle which produces the birdsong and the second task is to rotate a number of cams.
12.
By 1912 the firm had perfected the " Pitman Windchest, " ( A " Wind Chest " is the large box, normally built of wood, upon which the sound producing pipes are " planted, " and which contains the valves and mechanisms which control the wind supply to the pipes ) to a state of simple technical elegance.
