122 CLIMATIC CONDITIONS 



force of the winds accompanying them. The fall of the barometer in the 

 center of these storms is more rapid and is greater than in the case of tem- 

 perate region cyclones. Their rate of movement is considerably less; this is 

 a fortunate circumstance, as it enables us after once detecting the presence 

 of such storms by means of telegraphic reports to give ample v^arning of the 

 probable path of the storm. As they recurve northward and enter our lati- 

 tudes, they gradually enlarge their area, at the same time losing in power, 

 and finally merge into the type of temperate region cyclones which originate 

 in the Gulf of Mexico. 



In the destructive violence of the accompanying winds, the hurricane is 

 second only to the tornado of the Mississippi Valley. The area of disturb- 

 ance in the hurricane is, however, very much larger than that of the tornado. 

 Some idea of the tremendous power exhibited in these tropical storms is sug- 

 gested by Pigs. 1 and 2, Plate VII. These illustrations show a portion of the 

 shore of one of the small islands of the Bahama group. The huge rocks seen 

 in the foreground, some of .them weighing several tons, were torn up and 

 piled upon the beach by the force of the hurricane winds and waves. 



The premonitory signs and physical features of hurricanes are well 

 described by Mr. Bigelow in the following paragraph quoted from a paper on 

 " Cyclones, Hurricanes and Tornados " in the Yearbook of the U. S. Depart- 

 ment of Agriculture for 1898, at page 531. 



" The physical features of hurricanes are well understood. The approach of 

 a hurricane is usually indicated by a long swell on the ocean, propagated to great 

 distances and forewarning the observer by two or three days. A faint rise in the 

 barometer occurs before the gradual fall, which becomes very pronounced at the 

 center; fine wisps of cirrus clouds are first seen, which surround the center to a 

 distance of 200 miles; the air is calm and sultry, but this is gradually supplanted 

 by a gentle breeze, and later the wind increases to a gale, the clouds become 

 matted, the sea rough, rain falls, and the winds are gusty and dangerous as the 

 vortex core comes on. Here is the indescribable tempest, dealing destruction, 

 impressing the imagination with its wild exhibition of the forces of nature, the 

 flashes of lightning, the torrents of rain, the cooler air, all the elements in an 

 uproar, which indicate the close approach of the center. In the midst of this 

 turmoil there is a sudden pause, the winds almost cease, the sky clears, the waves, 

 however, rage in great turbulence. This is the eye of the storm, the core of the 

 vortex, and it is, perhaps, twenty miles in diameter, or one-thirtieth of the whole 

 hurricane. The respite is brief, and is followed by the abrupt renewal of the 

 violent wind and rain, but now coming from the opposite direction, and the storm 

 passes off with the several features following each other in the reverse order." 



The duration and continuity of these storms vary greatly. In his paper 



