"It's nasty weather like this here that turns heads grey before
their time," he said, with a nod toward the pilot-house.

"I had not thought there was any particular strain," I answered.
"It seems as simple as A, B, C. They know the direction by
compass, the distance, and the speed. I should not call it
anything more than mathematical certainty."

"Strain!" he snorted. "Simple as A, B, C! Mathematical
certainty!"

He seemed to brace himself up and lean backward against the air as
he stared at me. "How about this here tide that's rushin' out
through the Golden Gate?" he demanded, or bellowed, rather. "How
fast is she ebbin'? What's the drift, eh? Listen to that, will
you? A bell-buoy, and we're a-top of it! See 'em alterin' the
course!"

From out of the fog came the mournful tolling of a bell, and I
could see the pilot turning the wheel with great rapidity. The
bell, which had seemed straight ahead, was now sounding from the
side. Our own whistle was blowing hoarsely, and from time to time
the sound of other whistles came to us from out of the fog.

"That's a ferry-boat of some sort," the new-comer said, indicating
a whistle off to the right. "And there! D'ye hear that? Blown by
mouth. Some scow schooner, most likely. Better watch out, Mr.
Schooner-man. Ah, I thought so. Now hell's a poppin' for
somebody!"