In our passage to the island of St. Catherine's, we found the direction of the trade-winds to differ considerably from what we had reason to expect, both from the general histories given of these winds, and the experience of former navigators. For the learned Dr. Halley, in his account of the trade-winds which take place in the Ethiopia and Atlantic Ocean, tells us that from the latitude of 28° N., to the latitude of 10° N., there is generally a fresh gale of N.E. wind, which towards the African side rarely comes to the eastward of E.N.E., or passes to the northward of N.N.E.; but on the American side the wind is somewhat more easterly, though most commonly even there it is a point or two to the northward of the east. That from 10° N. to 4° N., the calms and tornadoes take place; and from 4° N. to 30° S., the winds are generally and perpetually between the south and the east. This account we expected to have verified by our own experience; but we found considerable variations from it, both in respect to the steadiness of the winds, and the quarter from whence they blew. For though we met with a N.E. wind about the latitude of 28° N., yet from the latitude of 25° to the latitude of 18° N., the wind was never once to the northward of the east, but, on the contrary, almost constantly to the southward of it. However, from thence to the latitude {41} of 6° 20' N., we had it usually to the northward of the east, though not entirely, it having for a short time changed to E.S.E. From hence, to about 4° 46' N., the weather was very unsettled; sometimes the wind was N.E. then changed to S.E., and sometimes we had a dead calm attended with small rain and lightning. After this, the wind continued almost invariably between the S. and E., to the latitude of 7° 30' S.; and then again as invariably between the N. and E., to the latitude of 15° 30' S.; then E. and S.E., to 21° 37' S. But after this, even to the latitude of 27° 44' S., the wind was never once between the S. and the E., though we had it at all times in all the other quarters of the compass. But this last circumstance may be in some measure accounted for from our approach to the main continent of the Brazils. I mention not these particulars with a view of cavilling at the received accounts of these trade-winds, which I doubt not are in general sufficiently accurate; but I thought it a matter worthy of public notice that such deviations from the established rules do sometimes take place. Besides, this observation may not only be of service to navigators, by putting them on their guard against these hitherto unexpected irregularities, but is a circumstance necessary to be attended to in the solution of that great question about the causes of trade-winds, and monsoons, a question which, in my opinion, has not been hitherto discussed with that clearness and accuracy which its importance (whether it be considered as a naval or philosophical inquiry) seems to demand.