Robert, sensing the professor’s misgivings, apologized for not having considered his difficulty in negotiating the unfamiliar interior in the darkness, and relieved him by entering first. A sharp click, and a comfortable glow of light suffused the interior. They passed up a brief, winding stairway into a long chamber.
“This is the gyrostatic control which neutralizes the force of gravity,” Robert began, calmly, as if this assertion were the simplest thing in the world. He indicated a complicated mass of glittering machinery in the center of the compartment in which they stood.
He reached for a small lever, and pulled it toward him. Simultaneously there was a soft whirring sound. For a moment the floor tilted slightly, then steadied again.
“And the power for this?” queried the professor.
“Furnished by storage batteries,” Robert explained. “The batteries are recharged by petrol-driven dynamos.”
“But your supply of petrol? Where have you sufficient space for a supply that will last any considerable length of time?”
“All round us.”
The professor swept their surroundings with his sharp eyes. No receptacle was visible. Two full-size doors and several small ones appeared in the partitions; but nothing suggested a receptacle for a large supply of fuel. Then quite suddenly it dawned upon him that there was a vast amount of space unaccounted for between the partitions, floor and ceiling, and the Sphere’s outside shell. His respect for Robert’s claims was growing. So far, at least, the young inventor seemed quite confident.
“What is this?” asked the professor, indicating what resembled the breech of a dreadnaught’s gun protruding from the floor. Electric wires, dials, and other curious devices were connected to it.
“That’s the Norrensen Tube, so named by my father after its inventor, an old friend of his, now deceased. It is capable of terrible destruction. It will produce a bolt of lightning rivaling the elements, which will strike up to twelve miles away—and it can be aimed with startling accuracy. I remember seeing a giant oak blasted into pulp with it in a test across a valley four miles wide, when I was a boy.”