cid went down that hole,
or others like it. Where is it now?"

"I suppose," said Boston, thoughtfully, "that it soaked up into the
hold, through the skin."

"Exactly. The skin is calked with oakum, is it not?" Boston nodded.

"That oakum would contract with the charring action, as did the oakum
in the hatch, and every drop of that acid--ten thousand gallons, as I
have figured--has filtered up into the hold, with the exception of what
remained between the frames under the skin. Have you ever studied
organic chemistry?"

"Slightly."

"Then you can follow me. When tallow is saponified there is formed,
from the palmitin, stearin, and olein contained, with the cauticizing
agent--in this case, lime--a soap. But there are two ends to every
equation, and at the bottom of this immense soap vat, held in solution
by the water, which would afterwards be taken up by the surplus lime,
was the other end of this equation; and as the yield from tallow of
this other product is about thirty per cent., and as we start with
eight thousand fifty-pound kids--four hundred thousand pounds--all of
which has disappeared, we know that, sticking to the skin and sides of
the barrels down here, is--or was once--one hundred and twenty thousand
pounds, or sixty tons, of the other end of the equation--glycerine!"

"Do you mean, Doc," asked Boston, with a startled look, "that--"

"I mean," said the doctor, emphatically, "that the first thing the
acids--mixed in the 'tween-deck to just about the right proportions,
mind you--would attack, on oozing through the skin, would be this
glycerine; and the certain product of this union under intense
cold--this hull was frozen in the ice, remember--would be
nitro-glycerine; and, as the yield of the explosive is two hundred and
twenty per cent. of the glycerine, we can be morally sure that in the
bottom of this hold, each minute globule of it held firmly in a hard
matrix of sulphate or nitrate of calcium--which would be formed next
when the acids met the hydrates and carbonates of lime--is over one
hundred and thirty tons of nitro-glycerine, all the more explosive from
not being washed of free acids. Come up on deck. I'll show you
something else."

Limp and nerveless, Boston followed the doctor. This question was
beyond his seamanship.

The doctor brought the yellow substance--now well dried. "I found
plenty of this in the 'tween-deck," he said; "and I should judge they
used it to pack between t