“For simplicity the area of low barometer is made perfectly circular and the center is assumed to be ten points to the right of the direction of the wind at all points within the disturbed area. Let us assume that the center is advancing about north-northeast, in the direction of the long arrow, shown in the heavy full line. The ship _a_ has the wind at east-northeast; she is to the left of the storm track, or technically in the navigable semicircle. The ship _b_ has the wind at east-southeast and is in the dangerous semicircle.***A vessel hove to at the position marked _b_, and being passed by the storm center, will occupy successive positions in regard to the center from _b_ to _b_4, and will experience shifts of the wind, as shown by the arrows, from east through south to southwest. On the other hand, if the storm center be stationary or moving slowly and a vessel be overtaking it along the line from _b_4 to _b_, the wind will back from southwest to east, and is likely to convey an entirely wrong impression as to the location and movement of the center. Hence it is recommended that a vessel suspecting the approach of proximity of a cyclonic storm should stop for a while until the path of the center is located by observing the shifts of the wind and the behavior of the barometer.” The movement of the winds around the storm center shown in this diagram is that of cyclones of the northern hemisphere; i. e., contrary to the direction of the clock hands. In the southern hemisphere they blow in the opposite direction around the center. [Illustration: NAVIGATION OF A SHIP IN A CYCLONIC STORM (_U. S. Hydrographic Office._)] By observing the rise or fall of the barometer, the shift of the winds, and the state of the sea and sky, the experienced navigator is generally able to lay down on a chart the approximate position of the storm center and steer his vessel so as to avoid danger. Various devices, known as “storm cards,” “cyclonoscopes,” etc., have been used to aid in the process of locating a storm from shipboard observations. In the Far East mariners use for locating typhoons an ingenious combination of the storm card and the aneroid barometer, called the “barocyclonometer,” an invention of the Rev. J. Algué, director of the Philippine Weather Bureau.