The water of the lake is fresh and sweet, so long as it communicates with the Euphrates; when the communication is cut off it becomes very unpalatable, and those who dwell in the vicinity are no longer able to drink it.

This result is attributed to the connection of the lake with rocks of the gypsiferous series.
It is obvious that the only natural divisions of Chaldaea a proper are those made by the river-courses.

The principal tract must always have been that which intervenes between the two streams.

This was anciently a district some 300 miles in length, varying from 20 to 100 miles in breadth, and perhaps averaging 50 miles, which must thus have contained an area of about 15,000 square miles.

The tract between the Euphrates and Arabia was at all times smaller than this, and in the most flourishing period of Chaldaea must have fallen short of 10,000 square miles.
We have no evidence that the natural division of Chaldaea here indicated was ever employed in ancient times for political purposes.