noun: A device which regulates or controls some action of a machine through automatic feedback.

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Keely
8. Small negative ring, which is the governor of the propeller, associated with a polar bar that oscillates from the polar field to the depolar field, somewhat on the order of a magnetic needle, governing the action of the machine to any given number of revolutions. The sympathetic rotation that exists in the resonating centre of this ring holds the neutral centre in subservience to celestial radiation, whereby a certain order of sympathetic disturbances gives the sympathetic radiation the requisite power to draw it to itself, accomplishing what is called atmospheric suspension on the same principle as that of sympathetic suspension. [Newton of the Mind, Air-ship]