In those days there were no chronometers in use, and but few of our West India captains were in possession of a sextant, or indeed able to work a lunar observation. The latitude was accurately determined every day by measuring the altitude of the sun as it passed the meridian. To ascertain the longitude was a more difficult matter. They were obliged to rely mainly on their dead reckoning; that is, to make a calculation of the course and distance run daily, from the points steered by the compass and the rate as indicated by the log-line and half-glass. A reckoning on such a basis, where unknown currents prevail, where a vessel is steered wildly, or where the rate of sailing may be inaccurately recorded, is liable to many errors; therefore it was customary with all prudent masters, in those days, especially if they distrusted their own skill or judgment in keeping a reckoning to KEEP WELL TO THE EASTWARD. This was a general rule, and looked upon as the key to West India navigation. Sometimes a vessel bound to the Windward Islands, after reaching the latitude of her destined port, found it necessary to "run down," steering due west, a week or ten days before making the land. An incident occurred in those waters, a few weeks after we passed over them, which will illustrate this mode of navigation, and the consequences that sometimes attend it. A large brig belonging to an eastern port, and commanded by a worthy and cautious man, was bound to St. Pierre in Martinico. The latitude of that island was reached in due time, but the island could not bee seen, the captain having steered well to the eastward. The brig was put before the wind, and while daylight lasted every stitch of canvas was spread, and every eye was strained to catch a glimpse of the high land which was expected to loom up in the western horizon. This proceeding continued for several days; the brig carrying a press of sail by day, and lying to by night, until patience seemed no longer a virtue. The worthy captain began to fear he had not steered far enough to the eastward, but had been carried by unknown currents to leeward of his port, and that the first land he should make might prove to be the Musquito coast on the continent. He felt anxious, and looked in vain for a vessel from which he could obtain a hint in regard to his true position. Neither land nor vessel could he meet with.