Crash!
The crucible was falling, jerked from its place atop the lab bench! The electric cable which supplied its current was twisted about the professor's ankle, somehow unconsciously caught by his foot as he worked.
Molten glass burst out of the pot in a white-hot wave. Slopped over the composition floor in a steaming river. Engulfed table legs and radiator pipes alike.
And then, like a writhing snake, the high tension line from which the crucible cable stemmed was whipping down, torn loose by the jar of the professor's leap!
Down it came! Struck the floor once. Lashed against the glass-engulfed radiator pipes, bare wires flashing.
A ball of purple fire exploded at the contact point, while the cable jerked and twisted like a living thing. The laboratory was suddenly permeated with ozone's peculiar odor.
"Look out!" cried Mark again.
But already Professor Duchard had jerked his foot free of the crucible line. He shrank back under the long bench, away from the writhing cable.
An instant later the current went dead. The crackling ball of purple fire evaporated into thin air.