The sea is the source of water and the source of wind; for neither would blasts of wind arise in the clouds and blow out from within them, except for the great sea, nor would the streams of rivers nor the rain-water in the sky exist but for the sea ; but the great sea is the begetter of clouds and winds and rivers.
XenophanesThis upper limit, of earth at our feet is visible and touches the air, but below it reaches to infinity
Xenophanes