The original raison d'etre of the theatre organ was the accompaniment of silent films. Organ builders long before the advent of theatre organs had amused themselves from time to time by fitting effects to instruments, but with the theatre organ this practice came into its own as a means of increasing the realism of the depiction of silent films. Even after the coming of the talkie, theatre organs retained these effects, no doubt for their novelty value.

Silent picture effects were, sometimes, disparagingly referred to as the "Toy Counter"

Effects included:

Bird Whistle

Train Whistle

Syren

Boat Whistle

Fire Gong

Surf

Aeroplane

Klaxon Horn

Horses Hooves.

See further:

Percussions