270 THE PHYSICAL GEOGRAPHY OF THE SEA. 



CHAPTER XT. 



§ 501-526. — THE CLOUD REGION, THE EQUATORIAL CLOUD- 

 RING, AND SEA FOGS. 



501. To simplify tlie discussion of these phenomena, let ns con- 

 cioud region-high- sider fogs at sea to be in character like clouds in 

 estinthecairabeit3. ^-^Q skj. So treating them, and confining our at- 

 tention to them as they appear to the mariner, we discover that 

 the cloud region in the main is highest in the trade- wind and calm 

 belts, lowest in extra-tropical regions. 



502. At sea, beyond " the offings," fogs are rarely seen between 

 Fogiess regions, the parallels of 30° N. and S. Sea fogs, therefore, 



may be considered a rare phenomenon over one half of the sur- 

 face of the globe. These fogiess regions, though certain parts of 

 them are not unfrequently visited by tempests, tornadoes, and 

 hurricanes, are nevertheless much less frequented by gales of 

 wind, as all furious winds are called, than are the regions on the 

 polar side of these two parallels. 



503. Taking the Atlantic Ocean, north and south, as an index 

 The most stormy lati- ^f what takcs placc ou othcr watcrs, the abstract 

 ^^'^^^^ logs of the Observatory show, according, to the 

 records of 265,304 observing days contained therein, that for ev- 

 ery gale of wind that seamen encounter on the equatorial side 

 of these two parallels of 30° N. and S., they encounter 10.4 on 

 the polar side, and that for every fog on the equatorial they en- 

 counter 83 on the polar side. As a rule, fogs and gales increase 

 both in numbers and frequency as you recede from the equator. 

 The frequency of these phenomena between the parallels of 5° 

 N. and 5° S., compared with their frequency between the paral- 

 lels of 45° and 50° IST. and S., is as 1 to 103 for gales, and as 1 to 

 102 for fogs. The observations do not extend beyond the paral- 

 lels of 60°. It appears from these, however, that both the most 

 stormy and foggy latitudes in the jSTorth Atlantic are between the 

 parallels of 45° and 50° ; that in the South Atlantic the most 



