they seemed to be connected, the one to the other, with a series of
endless belts, which Smith thought indicated automatic production. To
all appearances, the dust-covered apparatus stood just as it had been
left when operations ceased, an unguessable length of time before.

Smith showed no desire to touch the things now. Seeing this, the
geologist deliberately reached out and scraped the dust from the nearest
machine; and to the vast relief of all three, no damage was done. The
dust fell straight to the floor, exposing a brilliantly polished streak
of greenish-white metal.

Van Emmon made another tentative brush or so at other points, with the
same result. Clean, untarnished metal lay beneath all that dust. Clearly
it was some non-conducting alloy; whatever it was, it had successfully
resisted the action of the elements all the while that such presumably
wooden articles as the desk and railing had been steadily rotting.

Emboldened, Smith clambered up on the frame of one of the machines. He
examined it closely as to its cams, clutches, gearing, and other details
significant enough to his mechanical training. He noted their
adjustments, scrutinized the conveying apparatus, and came back carrying
a cylindrical object which he had removed from an automatic chuck.

"This is what they were making," he remarked, trying to conceal his
excitement. The others brushed the dust from the thing, a huge piece of
metal which would have been too much for their strength on the earth.
Instantly they identified it.

It was a cannon shell.