d, but neither Manuel nor himself was armed.
Suddenly--he had looked away for a moment--the bird was gone. Clutching
a short miner's pick-ax, and a little ashamed of his momentary
timidity, he strode to the edge of the abandoned shaft and peered down.
There was nothing to see; only rotting joists of wood, crumbling earth
for a few feet, and then darkness.

He pondered for a moment. This was the old Wiley claim. He knew it
well. The shaft went down for over two hundred feet, and there were
several lateral workings, one of which tunneled back into the hills for
a considerable distance. The mine had been a bonanza back in the days
when Oracle boomed, but the last ore had been taken out in 1905, and
for twenty-seven years it had lain deserted. Manuel came up beside him
and leaned over.

"What is that?" he questioned.

Talbot heard it himself, a faint rumbling sound, like the rhythmic
throb of machinery. Mystified, he gazed blankly at Manuel. Of course it
was impossible. What could functioning machinery be doing at the bottom
of an abandoned hole in the ground? And where there were no signs of
human activity to account for the phenomenon? A more forsaken looking
place it would be hard to imagine. Not that the surrounding country
wasn't ruggedly beautiful and grand; the hills were covered with
live-oak, yucca grass, chulla, manzanita, and starred with the white
blossoms of wild thistle. But this locality was remote from human
habitation, and lonely.

Could it be, Talbot wondered, the strange bird making that noise? Or
perhaps some animal? The noise sounded like nothing any creature,
furred or feathered, could make, but, of course, that must be the
explanation. However, it would be dark within the hour, with Oracle
still two miles distant, so he turned reluctantly away, Manuel
thwacking the burros from the grazing they had found. But that was not
to be the end of the odd experience. Just before the trail swung over
the next rise, Talbot glanced back. There, perching on the rim of the
abandoned mining shaft, were not one but two of the strange birds. As
if cognizant of his backward glance, they napped their gleaming,
metallic wings, although they did not rise, and gave voice to what
could only be their natural harsh cries, measured and, somehow,
sinister.

"_Toc-toc, toc-toc._"

Talbot went to bed determined to investigate the old Wiley claim the
next day, but in the morning an urgent telegram called him and Manuel