"The gun!" said he.
"I have thought of that," said I, for I made sure he was thinking of a bombardment of the fort. "They could never get the gun ashore, and if they did, they could never haul it through the woods."
"Look astern, doctor," replied the captain.
We had entirely forgotten the long nine; and there, to our horror, were the five rogues busy about her, getting off her jacket, as they called the stout tarpaulin cover under which she sailed. Not only that, but it flashed into my mind at the same moment that the round-shot and the powder for the gun had been left behind, and a stroke with an axe would put it all into the possession of the evil ones abroad.
I am guessing the long 9, is a large gun.
Yes..... Thank you Uncle Google:
he has forgotten the "long nine," a relatively light nine-foot-long cast-iron gun that they accidentally left on board the Hispaniola.