*Reference:** **Disturbance Theory*

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This was the title of a lecture given by Einstein at King’s College, London, 1921. It was published in *Mein Weltbild*, Amsterdam: Querido Verlag, 1934.

The Disturbance Theory summarizes this lecture as follows.

**SPECIAL THEORY OF RELATIVITY: The ratio of space and time is constant, because they both are characteristics of the same field in terms of wavelength and period. Space and time contract and expand together with frequency.**

**GENERAL THEORY OF RELATIVITY: Inertia is generated by frequency and rotation. Gravitation is generated by frequency and gradient. Rotation is balanced by gradient. Therefore, inertial mass is equivalent to gravitational mass.**

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