came a pressure on Frank's ear drums like the air-lock of a caisson.
Frank threaded his way amid pumps and feed water heaters and descended
still further to the furnace level.

Twenty-five knots--twenty-eight land miles an hour--was the speed of the
Plymouth at that moment. It was good going.

Below, instead of dust, heat, the clatter of shovels, grimy, sweating
fireman, such as the thought of the furnace room of a ship of war calls to
the mind of the landsman, a watertender stood calmly watching the glow of
oil jets feeding the furnace fire. Now and then he cast an eye to the
gauge glasses. The vibration of the hull and the hum of the blower were
the only sounds below.

For the motive power of the Plymouth was not furnished by coal. Rather, it
was oil--crude petroleum--that drove the vessel along. And though oil has
its advantage over coal, it has its disadvantages as well. It was Frank's
first experience aboard an oil-burner, and he had not become used to it
yet. He smelled oil in the smoke from the funnels, he breathed it from the
oil range in the galley. His clothes gathered it from stanchions and
rails.

The water tanks were flavored with the seepage from neighboring
compartments. Frank drank petroleum in the water and tasted it in the
soup. The butter, he thought, tasted like some queer vaseline. But Frank
knew that eventually he would get used to it.

"How's she heading?" Frank asked of the chief engineer.

"All right, sir," was the reply. "Everything perfectly trim. I can get