render the heat quite unsupportable. The nights are, nevertheless, often
clear and serene.

[Footnote 81: Dampier's Voyages, vol. iii. p.10.--Captain Krusenstern
appears to be of the same opinion, as to the Cape de Verde islands being
of sufficient magnitude to alter the direction of the trade winds,
remarking that S.W. winds are frequently met with there, and that if
they are not, the wind is always very moderate in their vicinity. He
recommends vessels, on their passage to the equator, to take their
course to the westward of these islands, so as to cross the parallel of
17 deg., or that of the island of Antonio in 26-1/2 deg., or even that of 27 deg.,
and then to steer S.E. by S. directly to the equator. He further
advises, that, if possible, the passage of the Line be effected in 20 deg.
or 21 deg., as then there is the advantage of a directly free wind as soon
as the S.E. trade sets in, and of course the ship gets quicker to the
southward. But this can rarely be done. He himself crossed the equator
in 24 deg. 20' W., after a passage of thirty days from Santa Cruz. Ships, he
informs us, when crossing in a more westerly direction than 25 deg. and 26 deg.,
have been driven by strong currents, and a too southerly trade wind, so
near the coast of Brazil, as not to be able to clear Cape St Augustin.
The present opportunity is taken of mentioning, that this very cautious
and intelligent navigator agrees, in general, with Cook, as to
Nichelson's rule. "His instructions for crossing the Line, on the voyage
to India, with 6 deg. 30' and 7 deg. 00' west variation, but in returning to
Europe, with eight degrees, might have been of use forty years ago, when
the method of finding the longitude at sea by distances of the sun and
moon was known to very few navigators, and for a time no great error was
committed by pursuing them; but at present a variation of seven degrees
would hardly be found on the coast of Africa."--The reason is, as the
scientific reader must know, that the variation has been on the western
increase since the period alluded to. Thus Nichelson found it at St
Helena, in 1764, to be 11 deg. 38', and Captain Krusenstern, in 1806, a
space of forty-two years, 17 deg. 18' 10".--E.]

At nine o'clock in the morning of the 13th, we arrived before Port
Praya, in the island of St Jago, where we saw two Dutch East India
ships, and a small brigantine, at anchor. As the Discovery was not
there, and we had expended but littl