17 Feb. 1815

Didacologia

Ch. Art & Science Division

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In so far as human observation has been able to apply itself to the subject, absolute motion is at all times among the inherent inseparable properties of every distinct body, and, in so far, of every particle of matter. But of relative motion, motion as between any two bodies or particles of matter considered in relation to one another, examples, real or apparent, may upon the surface of this our globe be found in abundance.

Of relative motion or its negation relative rest, no idea can, it should seem, be formed, otherwise than by the help of the idea of time. Two distinct bodies, in so far as in the course of a given length of time, the distance that intervenes between them is observed to be, or appears to be, different, are observed to have been one or both in motion with reference to each other - to have been, one or other, or both of them, in a state of relative motion; - in so far as no difference in respect of the amount of the distance between them has been observed, or is supposed to be observable, they are considered /regarded/ as having been in a state of rest.

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