her to the northward or
the southward, with the wind about two points abaft the beam; by doing
which we may hope to get to leeward of the brig in about two hours from
now, when we can resume our course for Sierra Leone with a reasonable
prospect of running the brig out of sight before morning. And, as she
was heading to the northward when we last saw her, our best plan will be
to steer a southerly course. So, up helm, Simpson, and we will steer
west-south-west for the next two hours, keeping a sharp look-out for the
brig, meanwhile, that we may not run foul of her unawares."

We had been steering our new course about an hour when it became
apparent that a change of weather was brewing, though what the nature of
the impending change might be it was, for the moment, somewhat difficult
to guess. The appearance of the sky seemed to portend a thunderstorm,
for it had rapidly become overcast with dense masses of heavy, lowering
cloud, which appeared to have quite suddenly gathered from nowhere in
particular, obscuring the stars, yet not wholly shutting out their
light, for the forms of the cloud-masses could be made out with a very
fair degree of distinctness, and it would probably also have been
possible to distinguish a ship at the distance of a mile. It was the
presence of this light in the atmosphere, emanating apparently from the
clouds themselves, that caused me rather to doubt the correctness of the
opinion, pretty freely expressed by the men, that what was brewing was
nothing more serious than an ordinary thunderstorm, for I had witnessed
something of the same kind before, on the coast, but in a much more
marked degree, it is true; and in that case the appearance had been
followed by a tornado, brief in duration, but of great violence while it
lasted. I therefore felt distinctly anxious, the more so as it was
evident that the wind was dropping, and this I regarded as a somewhat
unfavourable sign. I hailed Simpson, and asked him what he thought of
the weather.

"Why, sir," replied he, "the wind's droppin', worse luck; and if it
should happen to die away altogether, or even to soften down much more,
we shall have to out oars and pull; for we must get out of sight of that
brig somehow, between this and to-morrow morning."

"Undoubtedly," said I. "But that is not precisely what I mean. What is
worrying me just now is the question whether there is anything worse
than thunder behind the rather peculiar appearance