82 STORMS AND WEATHER FORECASTS 



the storm, which places the center inhmd, so that the wliole eddy 

 can be charted. 



West India Imrricanes are c}' clonic in character, but on account 

 of the fact that the diameter of the whirling edd_y is much less 

 and the velocit}'' of rotation much greater than in the average 

 cyclone, it is customary to designate them as hurricanes. In other 

 words, the hurricane is a cyclone of small area Ijut of })owerful 

 vortical action, and consequently^ of great destru.ctive force. To 

 get a rough idea of the difference between storms, we might 

 classify them according to the diameter of the revolving mass of 

 air under their influence as follows : 



Cyclones, 1,000 to 2,000 miles ; hurricanes, 200 to 500 miles, 

 and tornadoes one-half mile to one mile. Then if a great quan- 

 titj^ of heat energy is liberated b}'^ profuse condensation of aque- 

 ous vapor near the storm centers, we might imagine their vortical 

 action and their destructive force to increase as their diameters 

 of rotation decrease. 



Charts XX to XXV show the progress, in twelve-hour inter- 

 vals, of the hurricane northeastward to New England. It will 

 probably leave the American continent at Nova Scotia and in 

 three or four days cross the Atlantic and make its appearance 

 on the northwest coast of Europe. 



Twenty-five years ago mariners depended on their own weather 

 lorcto warn them of coming storms; then, although the num- 

 ber of boats plying the seas was much less than it is now, ever}'' 

 severe storm that swept across them left death and destruc- 

 tion in its wake, and for days afterward tlie dead were cast up 

 by the subsiding waters and the shores were lined with wreckage. 

 Happily this is not now the case ; the angry waters and the 

 howling winds vent their fur^^ the one upon the other, while the 

 great mass of shipping, so long the pre}^ of the winds and waves, 

 rides safely at anchor in convenient harbors. 



The United States has the most extensive weather service in 

 the world, and its enormous practical utilit}^ is now universally 

 recognized. Careful estimates based on reports from interested 

 parties indicate that cold-wave signals effectively displayed in 

 advance of one severe cold wave sweeping across our country re- 

 sult in a saving of over $3,500,000, Avhile responsible marine 

 re[)re3entatives declare that each West India hurricane passing 

 up the Atlantic seaboard would destro}'' not less than $2,000,000 

 worth of property and many lives if danger signals were not dis- 

 played well in advance of its coming. 



