Bill was peering out into the star-strewn ebon gulf. Captain Brand pointed. He saw a tiny blue globe, swimming among the stars.
"There's the infernal thing! Carrying its cargo of horror to our earth!"
In a few moments Dr. Trainor, the Prince, and Paula came one by one up the ladder to the bridge. Trainor carried the tripod; the Prince brought a little black case which contained the strange vacuum tube with the cerium electrode, and its various accessories; Paula had a little calculating machine and a book of mathematical tables.
Trainor and the Prince set up the tripod in the center of the room, and mounted the little black case upon it. The apparatus looked not very different from a small camera. Working with cool, brisk efficiency, Paula began operating the calculating machine, taking numbers from the book, and calling out the results to the Prince, who was setting numerous small dials on the apparatus.
Dr. Trainor peered through a compact little telescope which was evidently an auxiliary part of the apparatus, training the machine on the tiny blue disk that was the messenger of doom from Mars. From time to time he called out numbers which seemed to go into Paula's calculations.
Looking curiously at Paula and the Prince, Bill could see no sign of an understanding between them. Both seemed absorbed in the problem before them. They were impersonal as any two collaborating scientists.
At last Dr. Trainor raised his eyes from the little telescope, and the Prince paused, with his fingers on a tiny switch. The induction coil, in the circuit of a powerful vitalium generator, was buzzing monotonously, while purple fire leapt between its terminals. Paula was still efficiently busy over the little calculating machine, pressing its keys while the motors whirred inside it.
"We're all ready," Trainor announced, "as soon as Paula finishes the integration." He turned to Bill and Captain Brand, who were eying the apparatus with intense interest. "If you will look inside this electron tube, when the Prince closes the switch, you will see a tiny green spark come into being. Just at the focus of the rays from the cerium electrode, inside the vitalium helix grid.
"That green spark is a living thing!"