We left Johanna with the southwest monsoon, which in the Indian Ocean and China Sea blows from June to September with the regularity of the trade-winds of the Atlantic, both in direction and force. There the favorable resemblance ends; for, in the region through which we were passing, this monsoon is overcast, usually gloomy, and excessively damp. The northeast monsoon, which prevails during the winter months, is clear and dry. The consequent struggle with shoe-leather, and the deterioration of the same, is disheartening. But, though surcharged with moisture, rain does not fall to any great extent in the open sea, nor until the atmospheric current impinges on land, when it seems to be squeezed, like a sponge by the hand, with resultant precipitation. Our conditions were therefore pleasant enough. Being under sail only, the wind went faster than we, giving a cooling breeze as it passed over; and it was as steady and moderate as it was fair for our next destination, Aden, to reach which we were now pointing for Cape Guardafui. The _Iroquois_ ran along steadily northward, six to eight knots, followed by a big sea, but so regular that she rolled only with a slow, steady swing, not disagreeable. The veiled sun showed sufficiently for sights, without burning heat, and by the same token we passed that luminary on our course; that is, he was north of us while at Johanna, and one day on this run we got north of him. This must have been after we had crossed the equator; for, being August, the sun was still north of the "Line." This reminds me that, the day we thus passed the sun, our navigator, usually very exact, applied his declination wrong at noon, which gave us a wrong latitude. For a few minutes the discrepancy between the observation and the log caused a shaking of heads; the log doubtless fell under an unmerited suspicion, or else we had encountered a current not hitherto noted in the books, the usual solvent in such perplexities. I may explain for the unlearned in navigation that declination of a heavenly body corresponds in the celestial sphere to the latitude of an object on the terrestrial. The sun, being a leisurely celestial globe-trotter, continually varies his latitude--declination--within a zone bounded by the two tropics; and the rule runs that when his declination is of the same name (north or south) as his direction from the ship at noon, the declination is added or subtracted, I now forget which, in the computation that ascertains the vessel's precise position. This has to be remembered when he is passed overhead, in the zenith; for then the bearing changes, while his declination remains of the same name. If the resulting error is large, of course the mistake is detected immediately; a slight difference might pass unnoted with dangerous consequences.