that vast place. By their aid we pursued our path, still following
the grooves till suddenly these came to an end. Now all around us was a
flat floor of rock which, as we perceived clearly when we pushed
aside the dust that had gathered thickly on it in the course of ages,
doubtless from the gradual disintegration of the stony walls, had once
been polished till it resembled black marble. Indeed, certain cracks
in the floor appeared to have been filled in with some dark-coloured
cement. I stood looking at them while Bickley wandered off to the right
and a little forward, and presently called to me. I walked to him,
Bastin sticking close to me as I had the other candle, as did the little
dog, Tommy, who did not like these new surroundings and would not leave
my heels.

"Look," said Bickley, holding up his candle, "and tell me--what's that?"

Before me, faintly shown, was some curious structure of gleaming rods
made of yellowish metal, which rods appeared to be connected by wires.
The structure might have been forty feet high and perhaps a hundred
long. Its bottom part was buried in dust.

"What is that?" asked Bickley again.

I made no answer, for I was thinking. Bastin, however, replied:

"It's difficult to be sure in this light, but I should think that it
may be the remains of a cage in which some people who lived here kept
monkeys, or perhaps it was an aviary. Look at those little ladders for
the monkeys to climb by, or possibly for the birds to sit on."

"Are you sure it wasn't tame angels?" asked Bickley.

"What a ridiculous remark! How can you keep an angel in a cage? I--"

"Aeroplane!" I almost whispered to Bickley.

"You've got it!" he answered. "The framework of an aeroplane and a jolly
large one, too. Only why hasn't it oxidised?"

"Some indestructible metal," I suggested. "Gold, for instance, does not
oxidise."

He nodded and said:

"We shall have to dig it out. The dust is feet thick about it; we can do
nothing without spades. Come on."

We went round to the end of the structure, whatever it might be, and
presently came to another. Again we went on and came to another, all of
them being berthed exactly in line.

"What did I tell you?" said Bickley in a voice of triumph. "A whole
garage full, a regular fleet of aeroplanes!"

"That must be nonsense," said Bastin, "for I am quite sure that these
Orofenans cannot make such things. Indeed they have no metal, and even
cut the throats of pigs with