"Within this courtyard is the second enclosure. Its terrace, of the same basalt as the outer walls, is about twenty feet high. Entrance is gained to it by many breaches which time has made in its stonework. This is the inner court, the heart of Nan-Tauach! There lies the great central vault with which is associated the one name of living being that has come to us out of the mists of the past. The natives say it was the treasure-house of Chau-te-leur, a mighty king who reigned long 'before their fathers.' As Chan is the ancient Ponapean word both for sun and king, the name means, without doubt, 'place of the sun king.' It is a memory of a dynastic name of the race that ruled the Pacific continent, now vanished—just as the rulers of ancient Crete took the name of Minos and the rulers of Egypt the name of Pharaoh.
"And opposite this place of the sun king is the moon rock that hides the Moon Pool.
"It was Stanton who discovered the moon rock. We had been inspecting the inner courtyard; Edith and Thora were getting together our lunch. I came out of the vault of Chau-te-leur to find Stanton before a part of the terrace studying it wonderingly.
"'What do you make of this?' he asked me as I came up. He pointed to the wall. I followed his finger and saw a slab of stone about fifteen feet high and ten wide. At first all I noticed was the exquisite nicety with which its edges joined the blocks about it. Then I realized that its colour was subtly different—tinged with grey and of a smooth, peculiar—deadness.
"'Looks more like calcite than basalt,' I said. I touched it and withdrew my hand quickly for at the contact every nerve in my arm tingled as though a shock of frozen electricity had passed through it. It was not cold as we know cold. It was a chill force—the phrase I have used—frozen electricity—describes it better than anything else. Stanton looked at me oddly.
"'So you felt it too,' he said. 'I was wondering whether I was developing hallucinations like Thora. Notice, by the way, that the blocks beside it are quite warm beneath the sun.'
"We examined the slab eagerly. Its edges were cut as though by an engraver of jewels. They fitted against the neighbouring blocks in almost a hair-line. Its base was slightly curved, and fitted as closely as top and sides upon the huge stones on which it rested. And then we noted that these stones had been hollowed to follow the line of the grey stone's foot. There was a semicircular depression running from one side of the slab to the other. It was as though the grey rock stood in the centre of a shallow cup—revealing half, covering half. Something about this hollow attracted me. I reached down and felt it. Goodwin, although the balance of the stones that formed it, like all the stones of the courtyard, were rough and age-worn—this was as smooth, as even surfaced as though it had just left the hands of the polisher.
"'It's a door!' exclaimed Stanton. 'It swings around in that little cup. That's what makes the hollow so smooth.'
"'Maybe you're right,' I replied. 'But how the devil can we open it?'
"We went over the slab again—pressing upon its edges, thrusting against its sides. During one of those efforts I happened to look up—and cried out. A foot above and on each side of the corner of the grey rock's lintel was a slight convexity, visible only from the angle at which my gaze struck it.