“An inflammable fire-extinguishing liquid!” cried Hawkins. “Why, can't you understand that—bah!”
He laid a course to the upper regions and I followed.
“Out here in the extension,” he explained, when we reached the top floor. “There!”
We stood in a bare room, whose emptiness was accentuated by the cold, electric light.
Furnishings it had none, save for the big tank in the center. This was a wooden affair, lined with lead.
Over the top, and some two feet above the tank proper, the heavy cover was suspended by a weird system of pulleys and electric wires. To the under side of the cover was fastened a big glass sphere filled with white stuff.
It was a remarkable contrivance.
“There—that's simple, isn't it?” said Hawkins, with a happy smile.
“It may be if you understand it.”
“Why, just look here. See that big glass ball? That's full of marble dust—carbonate of lime, you know. The tank is filled with weak sulphuric acid. When the ball drops into the acid—what happens?”