The change from the scene of wind-flecked blue sea, stately march of the swell, and thunderous roar and creaming froth of the breakers outside to the oil-smooth, mud-laden, strong-smelling river, with its tiny, swirling eddies here and there, its mangrove-lined banks, and its silence, through which the roar of the surf came to us over the intervening sand spit, mellowed and subdued by distance, was so marked that, although this was by no means my first experience of that kind of thing, I found myself rubbing my eyes as though I were by no means certain that I was awake; and I noticed others doing the same.  A sharp word from the skipper, however, cautioning all hands to maintain a smart look-out, soon brought to us the realisation of our surroundings; for the river here was narrow, being not more than half a mile wide, with a number of small islets dotted about it, any one of which might prove to be the hiding-place of a formidable foe.  When at length we had passed these without interference, and had reached the point where the river began to widen out somewhat, we were no better off, but rather the worse; for here the stream was encumbered with extensive sandbanks, to avoid which we were compelled to approach the margin of the river so closely that a well-arranged ambush might have practically annihilated us before we could have effected a landing through the thick, viscid mud and the almost impenetrable growth of mangroves that divided the waters of the river from the solid ground of the shore.  Fortunately for us, the slavers appeared unaccountably to have overlooked the admirable opportunities thus afforded for frustrating an attack; or possibly, as we thought, it was that they had fully relied upon the power of the decoy schooner to draw us away from the coast, and thus leave the way free for them to escape.