through that store-room and see what
else there is to eat, and I'll examine the cargo. I want to know where
that acid went."

They opened all the hatches, and while Boston descended to the
lazarette, the doctor, with his trousers rolled up, climbed down the
notched steps in a stanchion. In a short time he came up with a yellow
substance in his hand, which he washed thoroughly with fresh water in
Boston's improvised draw-bucket, and placed in the sun to dry. Then he
returned to the 'tween-deck. After a while, Boston, rummaging the
lazarette, heard him calling through the bulkhead, and joined him.

"Look here, Boston," said the doctor; "I've cleared away the muck over
this hatch. It's 'corked,' as you sailormen call it. Help me get it
up."

They dug the compacted oakum from the seams with their knives, and by
iron rings in each corner, now eaten with rust to almost the thinness
of wire, they lifted the hatch. Below was a filthy-looking layer of
whitish substance, protruding from which were charred, half-burned
staves. First they repeated the experiment with the smouldering rag,
and finding that it burned, as before, they descended. The whitish
substance was hard enough to bear their weight, and they looked around.
Overhead, hung to the under side of the deck and extending the length
of the hold, were wooden tanks, charred, and in some places burned
through.

"She must have been built for a passenger or troop ship," said Boston.
"Those tanks would water a regiment."

"Boston," answered the doctor, irrelevantly, "will you climb up and
bring down an oar from the boat? Carry it down--don't throw it, my
boy." Boston obliged him, and the doctor, picking his way forward,
then aft, struck each tank with the oar. "Empty--all of them," he said.

He dug out with his knife a piece of the whitish substance under foot,
and examined it closely in the light from the hatch.

"Boston," he said, impressively, "this ship was loaded with lime,
tallow, and acids--acids above, lime and tallow down here. This stuff
is neither; it is lime-soap. And, moreover, it had not been touched by
acids." The doctor's ruddy face was ashen.

"Well?" asked Boston.

"Lime soap is formed by the cauticizing action of lime on tallow in the
presence of water and heat. It is easy to understand this fire. One
of those tanks leaked and dribbled down on the cargo, attacking the
lime--which was stowed underneath, as all these staves we see o