I have ever seen. You have seen those clocks on Earth which work by the action of light photons? Well, this is a similar idea but embodying a different principle. This clock is definitely the brain of all these other balls. It works, I imagine, by the action of cosmic rays passing through the planet. Can't give you every detail right now; I'll have to get my instruments to work and see what they can analyze of the forces inside the globe."
"I have the uneasy feeling that it resembles a time bomb," muttered Val, staring at it. "It started to tick when we broke a circuit. How do we know but what at a given hour the whole thing will explode?"
"We don't," Townshend said grimly. "That's what I want to find out. If x-rays pass through the globe, so will others capable of analysis. You'd better set about helping me."
IMMEDIATELY there were further journeys to the surface and one by one detector instruments were carefully lowered, together with adding machines, automatic analyzers, and dozens of smaller attachments necessary to a complete survey. Townshend worked steadily, tireless and grim, checking and computing, apparently heedless of the rather distracting ominous beating of the mighty pendulum.
"I think," Townshend said finally, glancing up with a strained face, "at the present moment this giant ball is establishing an electromagnetic contact with Earth's center."
"What!"
Townshend pored over the instruments and notes again, waved an impatient hand.
"Leave me alone for a while; I want to be sure about this. We're heading for something mighty tough if you ask me."
There was nothing the other engineers could do but pace around until they decided to utilize their enforced idleness by cremating the bodies round the elevator base. Once it was done they stood for a while with heads bowed amidst the smoke of the gun discharges, then they returned quietly to the ball room. Townshend greeted them with a shout.
"Boys, we've got to stop this damn thing somehow! We've eighteen hours to do it in—no more! If we don't manage it the Earth will be pretty near blown in pieces by volcanic fires, earthquake, and God knows what else. Listen here!"
He went on tensely,
"Between worlds there is a common affinity—a bond of gravitation which centers in the nickel iron core based on each planet, large or small. An electro-magnetic beam between worlds is bound to center on the exact center of each world. From here, the core of Mars, an electromagnetic beam is already being generated by the mechanism inside this ball. It has crossed the gap to Earth and automatically centers on the gravitative core of Earth. Earth and Mars are now chained by an invisible but unimaginably strong tunnel, its walls being forced, its apparently empty center being a path down which radiations can pass. Clear so far?"
"Go on," Cliff invited grimly.
"These instruments prove there is a potential force inside this globe of something like one million billion volts of energy, all of which will be released in one unthinkably terrible battering ram of force when the escape mechanism operates.
"Now, a force of that kind hurled through the electromagnetic beam—tube—and striking the magnetic center of Earth will create terrific havoc. The impact alone will be bad enough, but
