"I mean no harm," the strange telepathic voice said. "Your coming has brought hope to the world–where I am one of a dozen survivors. But–you cannot understand. I must show you. Watch that machine."
He gestured, and Blake stared at a huge machine forty feet distant–a creation of gleaming metal and softly glowing lights. Abruptly the lights flashed out blindingly. Then in the place of the machine was a screen of lambent radiance, oval, twenty feet tall. Shadows crawled across it. They grew clearer. They became–pictures!
A city flashed into the foreground, seen from the air–New York, in Blake's day. Yet Blake recognized odd discrepancies–an airplane flew past, and it was an awkward machine of pre-war days. A ship visible in the harbor was an old-fashioned sailing-vessel. The buildings were windowless.
"It is a reconstruction," Nak said. "Histories are not always accurate, especially when dealing with times so remote. Watch."
The scene shifted. There was a glimpse of racing green water. Another city grew–Sydney, Australia, Blake thought. It faded; there was only the white expanse of a sun-parched desert.
Abruptly there was a blinding flash of light–soundless. When it passed Blake saw a great crater, still smoking, gouged out of the desert.
"A meteor," Nak said. "The seed of the Doom."
The scene changed again. Now the desert seemed less arid as though dozens, perhaps hundreds of years, had passed. At the bottom of the crater was visible a little splotch of black. It glittered in the glaring sunlight.
"That is the Doom," Nak said, and there was hatred in his voice. "That entity, from intergalactic space, has wiped out all life from earth–all but a few hundreds. What it is we never discovered–not though we experimented with it for thousands of years. It is alive, but it is matter of an entirely different atomic type from matter that we know. It is not crystalline, nor mineral, nor organic at all–yet it is alive. And it eats. It ingests all matter–stone and sand and water, and even air, are all alike to it. Watch."
On the screen there appeared suddenly a great boulder, on which a tree, rooted in a little cup of soil, grew precariously. Into the picture a finger of blackness crept. It moved forward slowly, engulfing the stone and the tree. They were swallowed in the blackness.
"Earth had nothing that could stop it. It moved outward from the Australian desert–and downward too. Through the centuries it has grown until the solid earth, save for one 'island,' consists of nothing but that substance. Like an infection, it has eaten its way through steel and solid rock. It grew very slowly at first. Then faster and faster–perhaps forty thousand years ago man realized that it was a menace. It had covered only eighty square miles then. Its rate of growth increased tremendously, and there was nothing that could stop it.
"It has eaten earth, all but a small island, where the last remnants of humanity are gathered. In a circle about this central doomed city are the Outposts. This is an Outpost–one of a group of towers scattered about the edge of the island, to battle the Doom."
"You–battle it?" Blake asked.
The other nodded. "Yes. Now that it is too late, we have discovered how to destroy it. Through atomic destruction we disintegrate it–shatter the atoms of which it is composed. But we have so
