acts moisture. Again, if a fire is made in that place, and if the
ground, when thoroughly warmed and burned, sends up a misty vapour from
its surface, the place will contain water.

6. After applying these tests and finding the signs described above, a
well must next be sunk in the place, and if a spring of water is found,
more wells must be dug thereabouts, and all conducted by means of
subterranean channels into one place.

The mountains and districts with a northern exposure are the best spots
in which to search, for the reason that springs are sweeter, more
wholesome, and more abundant when found there. Such places face away
from the sun's course, and the trees are thick in them, and the
mountains, being themselves full of woods, cast shadows of their own,
preventing the rays of the sun from striking uninterruptedly upon the
ground and drying up the moisture.

7. The valleys among the mountains receive the rains most abundantly,
and on account of the thick woods the snow is kept in them longer by the
shade of the trees and mountains. Afterwards, on melting, it filters
through the fissures in the ground, and thus reaches the very foot of
the mountains, from which gushing springs come belching out.

But in flat countries, on the contrary, a good supply cannot be had. For
however great it is, it cannot be wholesome, because, as there is no
shade in the way, the intense force of the sun draws up and carries off
the moisture from the flat plains with its heat, and if any water shows
itself there, the lightest and purest and the delicately wholesome part
of it is summoned away by the air, and dispersed to the skies, while the
heaviest and the hard and unpleasant parts are left in springs that are
in flat places.

CHAPTER II

RAINWATER

1. Rainwater has, therefore, more wholesome qualities, because it is
drawn from the lightest and most delicately pure parts of all the
springs, and then, after being filtered through the agitated air, it is
liquefied by storms and so returns to the earth. And rainfall is not
abundant in the plains, but rather on the mountains or close to
mountains, for the reason that the vapour which is set in motion at
sunrise in the morning, leaves the earth, and drives the air before it
through the heaven in whatever direction it inclines; then, when once in
motion, it has currents of air rushing after it, on account of the void
which it leaves behind.

2. This air, driving the vapour