How are you going to market it?
Just what details have you worked out ?" Flint pondered a moment, before replying.

At last he said: "Of course you understand, Wally, I can't give you every point.

The whole thing will be an evolution, and new ideas and processes, new uses and demands will develop as time passes.

But in the main, my idea is this: The big producing stations will steadily extract oxygen from the atmosphere, thus leaving the air increasingly poorer and less adapted to sustaining human life.
"I shall store the oxygen in vast tanks, like the ordinary gas-tanks to be found in every city, only much bigger.

These tanks will be fed by pipe-lines from the central stations, thus." Flint drew toward him a sheet of his heavily embossed letter-paper, and, picking up a pencil, began to sketch a rough diagram.