[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°, or that of the island of Antonio in 26-1/2°, or even that of 27°, 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° or 21°, 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° 20' W., after a passage of thirty days from Santa Cruz. Ships, he informs us, when crossing in a more westerly direction than 25° and 26°, 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° 30' and 7° 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° 38', and Captain Krusenstern, in 1806, a space of forty-two years, 17° 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 little water in our passage from Teneriffe, I did not think proper to go in, but stood to the southward. Some altitudes of the sun were now taken, to ascertain the true time. The longitude by the watch, deduced therefrom, was 23° 48' west; the little island in the bay bore W.N.W., distant near three miles, which will make its longitude 23° 51'. The same watch, on my late voyage, made the longitude to be 23° 30' W.; and we observed the latitude to be 14° 53' 30" N.