390 THE POPULAR SCIENCE MONTHLY. 



apparently constructed with great care, like those mimic edifices of 

 sand made by children in their pastimes." The same writer also men- 

 tions a severe simoom which was " over in a couple of hours." 



Embedded in the great aerial currents, however, and supplied with 

 abundance of moisture, there is nothing to arrest either the rotatory 

 or progressive movements of the storm. Like the drift-bottles cast 

 upon the current of the ocean, and found after months to have been 

 carried thousands of miles, from the equatorial to the polar parallels, 

 there is every reason to suppose the tropic-cradled gale, and the minor 

 storms also, are borne in the great atmospheric currents through quite 

 as great distances. There is an authentic and well-attested account of 

 a Japanese junk, lost or deserted off Osaka, drifting through the im- 

 mense arc of the Kuro Siwo's recurvation, and encountered (in latitude 

 37, by the brig Forrester, March 24, 1815) off the coast of California. 

 That tiny craft must have followed in the bands of westerly winds and 

 warm waters for seventeen months. Why, upon theoretical grounds, 

 should we reject the hypothesis which represents the movement of 

 storm-areas as prolonged for many thousands of leagues, or indeed 

 that which represents them perpetually in motion around given cen- 

 tres of cyclonic or anti-cyclonic areas, keeping pace with the great 

 winds in their eternal circuit ? 



As a striking corroboration of all this we find what might have 

 been assumed on theoretical grounds that the logs and special obser- 

 vations of the Cunard steamships show that a vessel bound from 

 Liverpool westward encounters frequent advancing areas of low press- 

 ure, indicating a number of rapidly-succeeding barometric hollows 

 or depressions, "each with its own cyclonic wind-system, moving 

 across the Atlantic as eddies chasing each other down a river-cur- 

 rent." 



The word cyclone has frequently, but incorrectly, been used as 

 significant of an enormous or very violent meteor, as if its application 

 was to be confined to the devastating hurricane of the West Indies or 

 the terrific typhoon of the China seas. It simply means a storm which 

 acts in a circular direction, and whose winds converge, by radials or 

 sinuous spirals, toward a centre, moving in our hemisphere in the 

 opposite direction to that of the hands of a clock, and in the Southern 

 Hemisphere in a contrary direction. Taking this as the definition of 

 a cyclone, it seems clear, from observation alone, that all storms are to 

 be regarded as cyclonic. Volumes have been written to prove that 

 this is not the case. But we have only to examine a few series of 

 weather-maps from week to week to see that, wherever you have an 

 area of low barometer, into its central hollow the exterior atmosphere 

 from all sides will pour, and that in so doing a rotatory spiral or vor- 

 ticose storm is generated. The tornado, the simooms, the dust-whirl- 

 wind, the fire-storm, even the slow and sluggish storm which moves 



