In 1580, Bernard Palissy was the first man to describe the present day concept
of ‘water cycle’. He described how water evaporates from the oceans and
cools to form clouds. The clouds move inland where they rise, condense and
fall as rain. 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-Qur’aan 30:24]

“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.