1 6 HARBOUR CONSTRUCTION. 



If the observer should happen to be on the centre line of the 

 storm's path, the wind will appear to "jump " right round, it 

 may be, say, from north-east to south-west. 



In Northern Europe cyclones rarely pass so far to the 

 south as to give the backing sequence ; but when they do they 

 are almost always soon followed by another cyclone and fresh 

 bad weather. 



Along the north-east coast of Scotland, the wind usually 

 backs from south-west round by south to south-east in the worst 

 gales ; whereas along the west coast of Holland, it generally 

 veers from south-west round by west to north-west. 



Notwithstanding that the course of storms cannot be pre- 

 dicted with certainty, they appear, in the majority of cases, 

 to follow generally the direction of the predominant aerial 

 currents in which they are embedded, in much the same way 

 that eddies in a river follow ihe course of the stream, except 

 when deflected by obstructions or other influences. Hence in 

 the North Atlantic and over Great Britain, and other parts of 

 Northern Europe, the course of storms is generally easterly or 

 north-easterly, i.e. from west to east, or south-west to north- 

 east. In consequence of this, warning of their approach can 

 often be telegraphed from America several days before they 

 arrive. 



In the Mediterranean many of the storms travel southward, 

 being no doubt drawn in that direction by the ascending current 

 of hot air over Northern and Central Africa. Unlike those 

 further north, very few seem to travel to the eastward. In the 

 South Atlantic and Indian Oceans, they usually work round 

 from south-west to south-east or east. 



In many countries periodical winds and sequences of weather 

 recur with such regularity that forecasting is a simple matter. 

 Amongst such, monsoons are perhaps the most noteworthy. 

 These occur over the area occupied by the Indian Ocean, and 

 embrace the East Coast of Africa, India, Ceylon, etc. 



The south-west or warm wet monsoon prevails from April 

 to October; and the north-east or cold dry monsoon, from 

 October to April. Somewhat similar periodic winds also prevail 

 off the coasts of Brazil and Mexico. 



It is generally considered that monsoons are mere modifica- 

 tions of the " Trades." Vast tracts of land and sea, becoming 

 periodically heated by the sun's rays, produce ascending currents 



