Barker lever
Encyclopedia
The Barker lever is a pneumatic system which multiplies the force of a finger on the key of a tracker
Tracker action
Tracker action is a term used in reference to pipe organs and steam calliopes to indicate a mechanical linkage between keys or pedals pressed by the organist and the valve that allows air to flow into pipe of the corresponding note...

 pipe organ
Pipe organ
The pipe organ is a musical instrument that produces sound by driving pressurized air through pipes selected via a keyboard. Because each organ pipe produces a single pitch, the pipes are provided in sets called ranks, each of which has a common timbre and volume throughout the keyboard compass...

. It employs the wind pressure of the organ to inflate small bellows
Bellows
A bellows is a device for delivering pressurized air in a controlled quantity to a controlled location.Basically, a bellows is a deformable container which has an outlet nozzle. When the volume of the bellows is decreased, the air escapes through the outlet...

 called "pneumatics" to overcome the resistance of the pallets (valves) in the organ's wind-chest . This lever
Lever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

 allowed for the development of larger, more powerful organs still responsive to the human hand. These larger organs first flourished in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, e.g., the organ produced by Cavaill√©-Coll at St. Sulpice.

This "contrivance" was named after Charles Spackman Barker (1804-79), engineer and organ
Organ (music)
The organ , is a keyboard instrument of one or more divisions, each played with its own keyboard operated either with the hands or with the feet. The organ is a relatively old musical instrument in the Western musical tradition, dating from the time of Ctesibius of Alexandria who is credited with...

-builder. A similar lever was developed by David Hamilton in 1835, and there has been debate whether Barker stole the design. The rest of Barker's career was undistinguished.

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