Aina assured us that on the occasion of her former visit to the power house there had been but two sentinels on guard at the entrance. At the inner end of a long passage leading to the interior, she said, there were two more. Besides these there were three or four Martian engineers watching the machinery in the interior of the building. A number of airships were supposed to be on guard around the structure, but possibly their vigilance had been relaxed, because not long ago the Martians had sent an expedition against Ceres which had been so successful that the power of that planet to make any attack upon Mars had, for the present been destroyed.
Supposing us to have been annihilated in the recent battle among the clouds, they would have no fear or cause for vigilance on our account.
The entrance to the great structure was low—at least, when measured by the stature of the Martians. Evidently the intention was that only one person at a time should find room to pass through it.
Drawing cautiously near, we discerned the outlines of two gigantic forms, standing in the darkness, one on either side of the door. Colonel Smith whispered to me:
"If you will take the fellow on the right, I will attend to the other one."
Adjusting our aim as carefully as was possible in the gloom, Colonel Smith and I simultaneously discharged our disintegrators, sweeping them rapidly up and down in the manner which had become familiar to us when endeavoring to destroy one of the gigantic Martians with a single stroke. And so successful were we that the two sentinels disappeared as if they were ghosts of the night.
Instantly we all hurried forward and entered the door. Before us extended a long, straight passage, brightly illuminated by a number of electric candles. Its polished sides gleamed with blood-red reflections, and the gallery terminated, at a distance of two or three hundred feet, with an opening into a large chamber beyond, on the further side of which we could see part of a gigantic and complicated mass of machinery.
Making as little noise as possible, we pushed ahead along the passage, but when we had arrived within the distance of a dozen paces from the inner end, we stopped, and Colonel Smith, getting down upon his knees, crept forward, until he had reached the inner end of the passage. There he peered cautiously around the edge into the chamber, and, turning his head a moment later, beckoned us to come forward. We crept to his side, and, looking out into the vast apartment, could perceive no enemies.
What had become of the sentinels supposed to stand at the inner end the passage we could not imagine. At any rate, they were not at their posts.
The chamber was an immense square room at least a hundred feet in height and 400 feet on a side, and almost filling the wall opposite to us was an intricate display of machinery, wheels, levers, rods and polished plates. This we had no doubt was one end of the engine which opened and shut the great gates that could dam an ocean.