It is during these months that the phenomenon of the mirage is most remarkable.

The strata of air, unequally heated, and therefore differing in rarity, refract the rays of light, fantastically enlarging and distorting the objects seen through them, which frequently appear raised from the ground and hanging in mid-air, or else, by a repetition of their image, which is reflected in a lower stratum, give the impression that they stand up out of a lake.

Hence the delusion which has so often driven the traveller to desperation--the "image of a cool, rippling, watery mirror," which flies before him as he advances, and at once provokes and mocks his thirst.
The fertility of Chaldaea in ancient times was proverbial.
"Of all countries that we know," says Herodotus, "there is none that is so fruitful in grain.

It makes no pretension, indeed, of growing the fig, the olive, the vine, or any other tree of the kind; but in grain it is so fruitful as to yield commonly two hundred-fold, and when the production is at the greatest, even three hundred-fold.

The blade of the wheat-plant and of the barley-plant is often four fingers in breadth.