Alberuni remarked that brackishness of some degree is characteristic of sea water. God gave salt to sea water on purpose and the purpose was to prevent the water from turning foul and to guard against putrefaction which is harmful to living beings.⁶¹

As for the distribution of salinity in the oceans, Alberuni does not directly refer to this matter in his discussion but we gather from one of his statements that the distribution of salinity in oceans is related with the distribution of temperature on the surface of the earth. Hence, those seas which lie in the hot regions of the world have greater salinity than those in cold regions. He argues that 'As the Sun attracts moisture and evaporates [it] to dryness, and as it lifts up from the seas the lightest and the freshest, then what remains of sea water must be dense salt water which...