foot deep, a foot an' a half wide, an' as long
as could be made, slopin' slightly, so the water wouldn't run too fast
or too slow, an' wi' riffles every few inches all along. The six
claims I'm tellin' about give a chance for a sluice over a hundred
foot long. To save the trouble o' liftin' water up in a pail, or
pumpin' it, Father made a sort o' small flume, leadin' from the river
higher up right into the sluice, so's the water would run continuous.

"Bein' there was six o' them, the pardners worked three shifts, eight
hours each. One man dug the dirt, wheeled it in a barrow to the head
o' the sluice an' dumped it on a wooden platform. The other shoveled
it into the sluice, stirred it up, an' broke up the lumps when they
got pasty. Eight hours o' that was a day's work, I'm tellin'! Mother,
she cooked an' washed for all six men, aside lookin' after me. Wi'
meals to be got for all three shifts, she was kep' busy.

"The sluice didn't stop runnin', day nor night, for a month at a
stretch. Then the water in the flume was turned off, the sluice,
riffles an' platform were scraped clean wi' knives, an' all six
pardners panned the scrapin's. That was the clean-up. It was divided
by weight o' dust into seven equal parts, Mother gettin' a man's
share."

"Didn't they use any mercury at all on the Carson?" queried Owens.

"After a bit, our gang did. Not until each man had a bag o' dust set
aside, big enough to buy a few weeks' grub, though. They'd all got
badly bit in Californy, an' quicksilver cost a lot o' money in them
days."

"What's the quicksilver for?" queried Clem.

"To catch the gold. If you spread it on the riffles it seems to grab a
hold o' 'color' like glue, an', what's more, nothin' but gold'll stick
to it."

"Why is that?"

"I don't know," Jim answered, a bit irritably, "it does, that's all."

Owens interposed.

"You can't blame Jim for not knowing why, Clem," he said. "So far as
that goes, I don't believe any chemist in the world can tell you
exactly why quicksilver catches gold. It does, though, sure enough.
But I can show you how it does it, in a way.

"You know that if iron is exposed to damp air, it turns red with rust?
That is due to the chumminess or the affinity of iron with oxygen. You
know if silver is exposed to city air, where the burning of coal in
furnaces and fireplaces sends a sulphurous smoke into the air, it
turns black? That's due to the fact that silver is a natural chum of
sulphur.