The Billionaire’s eyes glittered as Herzog laid a hand on a gleaming switch.  Even Waldron forgot to smoke.

“Gentlemen, observe,” said Herzog, as he threw the lever.

CHAPTER VI.

OXYGEN, KING OF INTOXICATORS.

A soft humming note began to vibrate through the inner laboratory—­a note which rose in pitch, steadily, as Herzog shoved the lever from one copper post to another, round the half-circle.

“I am now heating the little firebrick furnace,” said the scientist.  “In Norway, they use an alternating current of only 5,000 volts, between water-cooled copper electrodes, as I have already told you.  I am using 30,000 volts, and my electrodes, my own invention, are—­”

“Never mind,” growled Flint.  “Just let’s see some of the product—­some liquid oxygen, that’s all.  The why and wherefore is your job, not ours!”

Herzog, with a pained smile, bent and peered through a red glass bull’s-eye that now had begun to glow in the side of his apparatus.

“The arc is good,” he muttered, as to himself.  “Now I will throw in the electro-magnets and spread it; then switch in my intensifying condenser, and finally set the turbine fans to work, to throw air through the field.  Then we shall see, we shall see!”

Suiting the action to the words, he deftly touched here a button, there a lever; and all at once a shrill buzzing rose above the lower drone of the induction coils.

“Gentlemen,” said Herzog, straightening up and facing his employers, “the process is now already at work.  In five minutes—­yes, in three—­I shall have results to show you!”

“Good!” grunted Waldron.  “That’s all we’re after, results.  That’s the only way you hold your job, Herzog, just getting results!”

He relighted his cigar, which had gone out during Herzog’s explanation—­for “Tiger” Waldron, though he could drop thousands at roulette without turning a hair, never yet had been known to throw away a cigar less than half smoked.  Flint, meanwhile, took out a little morocco-covered note book and made a few notes.  In this book he had kept an outline of his plan from the very first; and now with pleasure he added some memoranda, based on what Herzog had just told him, as well as observations on the machine itself.

Thus two minutes passed, then three.

“Time’s up, Herzog!” exclaimed Waldron, glancing at the electric clock on the wall.  “Where’s the juice?”

“One second, sir,” answered the scientist.  Again he peeked through the glowing bull’s-eye.  Then, his face slightly pale, his bulging eyes blinking nervously, he took two small flint glass bottles, set them under a couple of pipettes, and deftly made connections.

“Oxygen cocktail for mine,” laughed Waldron, to cover a certain emotion he could not help feeling at sight of the actual operation of a process which might, after all, open out ways and means for the utter subjugation of the world.