piral of smoke drew them to a canyon head where they found
three fishermen with a pack train of seven horses,--but no Mexicans. They
searched Southward along the John Muir trail, returning along the Eastern
flank,--but to no purpose, so far as the fugitives were concerned.

As no one had had time to fish, they dined on tinned corned beef, which
Ace, the cook for the day, made the mistake of salting. (After that he
had to make tea twice.)

"One thing I'd like fer to ask you, Mr. Norris," said Long Lester that
night around the bon-fire, "is where does the salt in the ocean come
from? I don't see for the life of me, from what you've told us----"

"The salt was originally in the rock of the earth's crust," Norris
explained with a pleased smile at the old man's interest. "As this
igneous rock weathered with time, the rain and the streams washed it into
the ocean. Then when the sea water evaporates----"

"To make clouds, to make more rain?" Long Lester recited.

"Yes,--the salt of course remained behind, so that the oceans have been
growing constantly saltier since the earth began. Yet even now sea water
must be nine-tenths evaporated before the sodium begins to precipitate,
as we say."

"So there is room for a lot more."

"Especially as the oceans are growing larger all the time."

"But doesn't the ocean give it back to the land when it leaves these
sediments along the shore?"

"Not to any extent, speaking comparatively. But one of the interesting
things about the salt in the sea is this: Chemists and geologists
estimate that, for the amount of salt in the sea, enough of the original
earth crust must have been weathered away to have covered the continents
over 6,000 feet high. And that calculation just about fits what we
believe to have happened.

"The United States Geological Survey gave out an official statement in
1912 that this country is annually being washed back into the ocean at
the rate of two hundred and seventy million tons of matter dissolved in
the streams and five hundred and thirteen millions of tons of matter held
in suspension in the same streams. That is to say, the oceans every year
receive from the surface of the United States seven hundred and
eighty-three millions of tons of rock materials.

"That means that, here in this part of the country at least, one hundred
and seventy-seven tons per square mile are being washed back each year."

"Gee!" said Ted. "I should think, at that rate, that th