Neither Flint nor the inventor vouchsafed even a smile.  The Billionaire drew near, adjusted a pair of pince-nez on his hawk-like nose, and peered curiously at the apparatus.  Herzog, with a quick gesture, turned a small silver faucet.

“Oxygen!  Unlimited oxygen!” he exclaimed.  “I have found the process, gentlemen, commercially practicable.  Oxygen!”

Even as he spoke, a lambent, sparkling liquid began to flow through the pipette, into the flask.  At sight of it, the Billionaire’s eyes lighted up with triumph.  Waldron, despite his assumed nonchalance, felt the hunting thrill of Wall street, the quick stab of exultation when victory seemed well in hand.

“These bottles,” said Herzog, “are double, constructed on the principle of the Thermos bottle.  They will keep the liquid gases I shall show you, for days.  Huge tanks could be built on the same principle.  In a short time, gentlemen, you can handle tons of these gases, if you like—­thousands of tons, unlimited tons.

“The Siemens and Halske people, and the Great Falls, S.C., plant, will be mere puttering experimenters beside you.  For neither they nor any other manufacturers have any knowledge of the vital process—­my secret, polarizing transformer, which does the work in one-tenth the time and at one-hundredth the cost of any other known process.  For example, see here?”

He turned the faucet, disconnected the flask and handed it to Flint.

“There, sir,” he remarked, “is a half-pint of pure liquid oxygen, drawn from the air in less than eight minutes, at a cost of perhaps two-tenths of a cent.  On a large scale the cost can be vastly reduced.  Are you satisfied, sir?”

Flint nodded, curtly.

“You’ll do, Herzog,” he replied—­his very strongest form of commendation.  “You’re not half bad, after all.  So this is liquid oxygen, eh?  Very cheap, and very cold?”

His eyes gleamed with joy at sight of the translucent potent stuff—­the very stuff of life, its essence and prime principle, without which neither plant nor animal nor man can live—­oxygen, mother of all life, sustainer of the world.

“Very cheap, yes, sir,” answered the scientist.  “And cold, enormously cold.  The specimen you hold in your hand, in that vacuum-protected flask, is more than three hundred degrees below zero.  One drop of it on your palm would burn it to the bone.  Incidentally, let me tell you another fact—­”

“And that is?”

“This specimen is the allotropic or condensed form of oxygen, much more powerful than the usual liquified gas.”

“Ozone, you mean?”

“Precisely.  Would you like to sense its effect as a ventilating agent?”

“No danger?”

“None, sir.  Here, allow me.”

Herzog took the flask, pressed a little spring and liberated the top.  At once a whitish vapor began to coil from the neck of the bottle.

“Hm!” grunted Waldron, smiling.  “Mountain winds and sea breezes have nothing on that!” He sniffed with appreciation.  “Some gas, all right!”