"Oh, come back," said Hawkins. "You can't get out, anyway, until I
undo the lock. But there's no danger whatever, my dear boy. Just sit
down and I'll explain why."

I had no choice about sitting down; a most peculiar weakness of the
knees made standing for the moment impossible. I drew my chair to the
diagonally opposite corner of the apartment, and sat there with my
eyes glued upon the vat.

"Now, when all these fellows go about nitrating their glycerine," said
Hawkins serenely, "they simply overlook the scientific principle which
I have discovered. For instance, out there at Pompton the vat exploded
in the very act of mixing in the glycerine. That's just what is being
done over in that corner at this minute----"

"Ouch!" I cried involuntarily.

"But it won't happen here--it can't happen here," said the inventor
impatiently. "I am using an entirely different combination of
chemicals. Now, if there was any trouble of that sort coming, Griggs,
the contents of that vat would have begun to turn green before now.
But as you see----"

"Haw--Hawkins!" I croaked hoarsely, pointing a shaking finger at the
machine.

"Well, what is it now?"

"Look!" I managed to articulate.