This water gathers as lakes and streams and flows back to the
ocean in a continuous cycle. In the 7th century B.C., Thales of Miletus
believed that surface spray of the oceans was picked up by the wind and
carried inland to fall as rain.
In earlier times people did not know the source of underground water. They thought the water of the oceans, under the effect
of winds, was thrust towards the interior of the continents.
They also believed that the water returned by a secret passage, or the Great Abyss. This passage is connected to the oceans and has been called the ‘Tartarus’, since Plato’s time.
Even Descartes, a great thinker of the eighteenth century, subscribed to
this view. Till the nineteenth century, Aristotle’s theory was prevalent.
According to this theory, water was condensed in cool mountain caverns and formed underground lakes that fed springs. Today, we know that the
rainwater that seeps into the cracks of the ground is responsible for this.
The water cycle is described by the Qur’aan in the following verses:
“Seest thou not that Allah Sends down rain from The sky, and leads it Through springs in the earth? Then He causes to grow, Therewith, produce of various Colours.” [Al-Qur’aan 39:21]
“He sends down rain From the sky And with it gives life to The earth
after it is dead: Verily in that are Signs For those who are wise.” [Al-
“And We send down water From the sky according to (Due) measure,
and We cause it To soak in the soil; And We certainly are able To drain
it off (with ease).” [Al-Qur’aan 23:18]
No other text dating back 1400 years ago gives such an accurate description of the water cycle.