he carboy boxes. It was once cotton-batting.
It is now, since I have washed it, a very good sample of gun-cotton.
Get me a hammer--crowbar--something hard."

Boston brought a marline-spike from the locker, and the doctor, tearing
off a small piece of the substance and placing it on the iron barrel of
a gipsy-winch, gave it a hard blow with the marline spike, which was
nearly torn from his hand by the explosion that followed.

"We have in the 'tween-deck," said the doctor, as he turned, "about
twice as many pounds of this stuff as they used to pack the carboys
with; and, like the nitro-glycerine, is the more easily exploded from
the impurities and free acids. I washed this for safe handling.
Boston, we are adrift on a floating bomb that would pulverize the rock
of Gibraltar!"

"But, doctor," asked Boston, as he leaned against the rail for support,
"wouldn't there be evolution of heat from the action of the acids on
the lime--enough to explode the nitro-glycerine just formed?"

"The best proof that it did not explode is the fact that this hull
still floats. The action was too slow, and it was very cold down
there. But I can't yet account for the acids left in the bilges. What
have they been doing all these fifty years?"

Boston found a sounding-rod in the locker, which he scraped bright with
his knife, then, unlaying a strand of the rope for a line, sounded the
pump-well. The rod came up dry, but with a slight discoloration on the
lower end, which Boston showed to the doctor.

"The acids have expended themselves on the iron frames and plates. How
thick are they?"

"Plates, about five-eighths of an inch; frames, like railroad iron."

"This hull is a shell! We won't get much salvage. Get up some kind of
distress signal, Boston." Somehow the doctor was now the master-spirit.

A flag was nailed to the mast, union down, to be blown to pieces with
the first breeze; then another, and another, until the flag locker was
exhausted. Next they hung out, piece after piece, all they could spare
of the rotten bedding, until that too was exhausted. Then they found,
in a locker of their boat, a flag of Free Cuba, which they decided not
to waste, but to hang out only when a sail appeared.

But no sail appeared, and the craft, buffeted by gales and seas,
drifted eastward, while the days became weeks, and the weeks became
months. Twice she entered the Sargasso Sea--the graveyard of
derelicts--to be blown out by friend