rstand you."

"What I mean is, that there is but little atmospheric change. It is but
one uniform drought; it is seldom tempestuous or rainy. I know some
districts where a drop of rain has not fallen for years."

"And can you account for that phenomenon?"

"I have my theory. It may not satisfy the learned meteorologist, but I
will offer it to you."

I listened with attention, for I knew that my companion was a man of
science, as of experience and observation, and subjects of the character
of those about which we conversed had always possessed great interest
for me. He continued--

"There can be no rain without vapour in the air. There can be no vapour
in the air without water on the earth below to produce it. Here there
is no great body of water.

"Nor can there be. The whole region of the desert is upheaved--an
elevated table-land. We are now nearly six thousand feet above sea
level. Hence its springs are few; and by hydraulic law must be fed by
its own waters, or those of some region still more elevated, which does
not exist on the continent.

"Could I create vast seas in this region, walled in by the lofty
mountains that traverse it--and such seas existed coeval with its
formation; could I create those seas without giving them an outlet, not
even allowing the smallest rill to drain them, in process of time they
would empty themselves into the ocean, and leave everything as it now
is, a desert."

"But how? by evaporation?"

"On the contrary, the absence of evaporation would be the cause of their
drainage. I believe it has been so already."

"I cannot understand that."

"It is simply thus: this region possesses, as we have said, great
elevation; consequently a cool atmosphere, and a much less evaporating
power than that which draws up the water of the ocean. Now, there would
be an interchange of vapour between the ocean and these elevated seas,
by means of winds and currents; for it is only by that means that any
water can reach this interior plateau. That interchange would result in
favour of the inland seas, by reason of their less evaporation, as well
as from other causes. We have not time, or I could demonstrate such a
result. I beg you will admit it, then, and reason it out at your
leisure."

"I perceive the truth; I perceive it at once."

"What follows, then? These seas would gradually fill up to overflowing.
The first little rivulet that trickled forth from their lipping fulness