The nights of early March in this latitude were exceedingly beautiful, and solemnly impressive was the liberal splendor of the sky. The full moon looked down upon and was reflected by waters of perfect smoothness. River navigation could not have been more quiet than were these nights on the blue Caribbean Sea. The air was as mild as June in New England, while at night the Southern Cross and the North Star blazed in the horizon at the same time. As we steered westward after doubling the cape, both of these heavenly sentinels were seen abeam, the constellation on our port side, and the North Star on the starboard. Each day, at the noon hour, the passengers were interested in watching the officers of the ship while they were "taking the sun," to determine the latitude and longitude. Shall we put the process into simple form for the information of the uninitiated? When the sun reaches the meridian, or culminating point of ascension, the exact moment is indicated by the instrument known as a quadrant, adjusted to the eye of the observer. The figures marked on the quadrant give the latitude of the ship at the moment of meridian. The ship's time is then made to correspond, that is to say, it must indicate 12 o'clock, M., after which it is compared with the chronometer's Greenwich time, and the difference enables the observer to determine the longitude. As fifteen miles are allowed to the minute, there will be nine hundred miles to the hour. The importance of absolute correctness in the chronometer will at once be realized, since, were it only three minutes out of the way, it would render the calculation as to longitude wrong by nearly fifty miles, which might be, and doubtless often has been, the cause of wrecking a ship upon rocks laid down upon the charts, but supposed to be far away. With the chronometer and the quadrant observation correctly ascertained, the sailing-master can prick off his exact situation on the chart. So long as the weather will permit a clear view of the sun at noon, the ship's precise location on the wide waste of waters can be known; but when continuous cloudy weather prevails, the ship's course is calculated by what is called dead reckoning, depending upon the speed and distance run as indicated by the log, which is cast hourly under such circumstances, and becomes the main factor in calculating the position of the ship. Of course the result cannot be very accurate, but is a dernier ressort. When land is in sight no observation is necessary, as the bearing of the ship is then unmistakably defined.