In the tropics day comes and goes with a rush, and, even while the skipper had been speaking, the object which had first revealed itself to me, a minute earlier, as a mere wan, ghostly suggestion had assumed solidity and definiteness of form, and now stood out against the sky behind her as a full-rigged ship of some seven hundred and fifty tons burthen, her hull painted bright green, and coppered to the water-line. She was lying stern-on to us, and sat deep in the water, from which latter fact one inferred that she had her cargo of slaves on board and had doubtless, as the skipper conjectured, come out of the river with the last of the land-breeze during the previous night, and had remained becalmed near us, and, we hoped, quite unaware of our proximity all night.  She was now within a cable's length of the boats, but, lying as she was, dead stern-on to us, we in the gig were unable to see how many guns she carried, which was, however, an advantage to us, since, however many guns she might mount on her broadsides, she could bring none of them to bear upon us.  We saw, however, that she carried two stern- chasers--long nine's, apparently--and now, in the hope of dashing alongside before those two guns could be cast loose and brought to bear upon us, the captain stood up in the stern-sheets of the gig and waved his arm to the other boats as a signal to them to give way--for, with the coming of the daylight we could not possibly hope to remain undiscovered above a second or two longer.