A dense mist hung over the ocean; the sky above our heads was of a grey tint; the water below our feet of the colour of lead. Not a ripple disturbed its mirror-like surface, except when now and then a covey of flying fish leaped forth to escape from their pursuers, or it was clove by the fin of a marauding shark. We knew that we were not far off the coast of Africa, some few degrees to the south of the Equator; but how near we were we could not tell,...