e period in the year, and that period has now arrived, when
there is special danger of a great deluge. Most of the oceans of Mars
lie in the southern hemisphere. When it is Summer in that hemisphere,
the great masses of ice and snow collected around the south pole melt
rapidly away."

"Yes, that is so," broke in one of our astronomers, who was listening
attentively. "Many a time I have seen the vast snow fields around the
southern pole of Mars completely disappear as the Summer sun rose high
upon them."

"With the melting of these snows," continued Aina, "a rapid rise in the
level of the water in the southern oceans occurs. On the side facing
these oceans the continents of Mars are sufficiently elevated to prevent
an overflow, but nearer the equator the level of the land sinks lower."

"With your telescopes you have no doubt noticed that there is a great
bending sea connecting the oceans of the south with those of the north
and running through the midst of the continents."

"Quite so," said the astronomer who had spoken before, "we call it the
Syrtis Major."

"That long narrow sea," Aina went on, "forms a great channel through
which the flood of waters caused by the melting of the southern polar
snows flows swiftly toward the equator and then on toward the north until
it reaches the sea basins which exist there. At that point it is rapidly
turned into ice and snow, because, of course, while it is Summer in the
southern hemisphere it is Winter in the northern."

Mars Will Be Ours.

"The Syrtis Major (I am giving our name to the channel of communication in
place of that by which the girl called it) is like a great safety valve,
which, by permitting the waters to flow northward, saves the continents
from inundation."

"But when mid-Summer arrives, the snows around the pole having been
completely melted away, the flood ceases and the water begins to
recede. At this time, but for a device which the Martians have employed,
the canals connected with the oceans would run dry, and the vegetation,
left without moisture under the Summer sun, would quickly perish."

"To prevent this they have built a series of enormous gates extending
completely across the Syrtis Major at its narrowest point (latitude 25
degrees south). These gates are all controlled by machinery collected
at a single point on the shore of the strait. As soon as the flood in
the Syrtis Major begins to recede, the gates are closed, and, the water
being