S by W │ W by N ║ S by W │ E by S SSW │ WNW ║ SSW │ ESE SW by S │ NW by W ║ SW by S │ SE by E SW │ NW ║ SW │ SE SW by W │ NW by N ║ SW by W │ SE by S WSW │ NNW ║ WSW │ SSE W by S │ N by W ║ W by S │ S by E West. │ North. ║ West. │ South. W by N │ N by E ║ W by N │ S by W WNW │ NNE ║ WNW │ SSW NW by W │ NE by N ║ NW by W │ SW by S NW │ NE ║ NW │ SW NW by N │ NE by E ║ NW by N │ SW by W NNW │ ENE ║ NNW │ WSW N by W │ E by N ║ N by W │ W by S ─────────────┴───────────────────╨─────────────┴──────────────────── The path which the axis of rotation describes is not inappropriately termed the “Axis Line.” On the “Axis Line” there is no change of wind until the center has passed, when, after a brief interval of calm, the wind springs up with great fury from the opposite quarter. It has been remarked by Piddington, “that he who watches his barometer, watches his ship.” This invaluable instrument, if well understood, invariably announces the approach of a revolving storm; shows whether the vessel is plunging into the vortex, or if she be receding from it; and hence, by carefully noticing its indications, the disastrous consequences of a hurricane may, to a great extent, be avoided,—for the laws of its oscillations are very distinctly marked. The barometer often stands unusually high before the commencement of a cyclone, and frequently (if not always) just around the storm. And conceiving the cyclone to be divided into two parts by a diameter at right angles to its path, it may be noted that the barometer always falls during the passage of the advancing semi-circle of a revolving storm. The barometer always rises during the passage of the receding semi-circle of a revolving storm. In cases of manɶuvering to take advantage of the hurricane winds, and to keep just within the verge of the storm, the barometer is of signal benefit,—it should be kept as high as possible, without losing the wind. In whatever position the ship may be, the rising of the mercury announces that the first (or dangerous) half of the storm has passed.