Humboldt, in his _Cosmos_,[6] gives the following beautiful
illustrative proofs of this phenomenon:
If, for a moment, we imagine the acuteness of our senses
preternaturally heightened to the extreme limits of telescopic
vision, and bring together events separated by wide intervals of
time, the apparent repose which reigns in space will suddenly
vanish; countless stars will be seen moving in groups in various
directions; nebulæ wandering, condensing, and dissolving like
cosmical clouds; the milky way breaking up in parts, and its
veil rent asunder. In every point of the celestial vault we
shall recognise the dominion of progressive movement, as on the
surface of the earth where vegetation is constantly putting forth
its leaves and buds, and unfolding its blossoms. The celebrated
Spanish botanist, Cavanilles, first conceived the possibility of
“seeing grass grow,” by placing the horizontal micrometer wire
of a telescope, with a high magnifying power, at one time on the
point of a bamboo shoot, and at another on the rapidly unfolding
flowering stem of an American aloe; precisely as the astronomer
places the cross of wires on a culminating star. Throughout the
whole life of physical nature--in the organic as in the sidereal
world--existence, preservation, production, and development, are
alike associated with motion as their essential condition.