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.