Omean: Miles below the surface of Barsoom this subterranean ocean is accessed through a 1,000 foot opening of an extinct volcano.
“For quite half an hour we descended and then the shaft terminated abruptly in the dome of a mighty subterranean world. Below us rose and fell the billows of a buried sea. A phosphorescent radiance illuminated the scene. Thousands of ships dotted the bosom of the ocean. Little islands rose here and there to support the strange and colourless vegetation of this strange world.
“Slowly and with majestic grace the battleship dropped until she rested on the water. Her great propellers had been drawn and housed during our descent of the shaft and in their place had been run out the smaller but more powerful water propellers. As these commenced to revolve the ship took up its journey once more, riding the new element as buoyantly and as safely as she had the air.
“Nearly all the vessels we saw were war craft. There were a few lighters and barges, but none of the great merchantmen such as ply the upper air between the cities of the outer world.
"Here is the harbour of the navy of the First Born," said a voice behind us, and turning we saw Xodar watching us with an amused smile on his lips.
"This sea,’ he continued, ‘is larger than Korus. It receives the waters of the lesser sea above it. To keep it from filling above a certain level we have four great pumping stations that force the oversupply back into the reservoirs far north from which the red men draw the water which irrigates their farm lands.’
“A new light burst on me with this explanation. The red men had always considered it a miracle that caused great columns of water to spurt from the solid rock of their reservoir sides to increase the supply of the precious liquid which is so scarce in the outer world of Mars. Never had their learned men been able to fathom the secret of the source of this enormous volume of water. As ages passed they had simply come to accept it as a matter of course and ceased to question its origin.
“We passed several islands on which were strangely shaped circular buildings, apparently roofless, and pierced midway between the ground and their tops with small, heavily barred windows. They bore the earmarks of prisons, which were further accentuated by the armed guards who squatted on low benches without, or patrolled the short beach lines. Few of these islets contained over an acre of ground, but presently we sighted a much larger one directly ahead. This proved to be our destination, and the great ship was soon made fast against the steep shore.” (GM VIII)
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