122 rnYsic^L GEOGRArny of the sea, akd its meteohology. 



this A\apour is condensed and precipitated, during this part of the 

 year, almost in constant showers, and to the depth of about 

 thirty inches in three months. 



296. TJie rainy seasons of California and Panama. — In tlie winter 

 the calm belt of Cancer approaches the equator. This whole 

 system of zones, viz., of trades, calms, and westerly winds, 

 follows the sun; and they of our hemisphere are nearer the 

 equator in the winter and spring months than at any other 

 season. The south-west winds commence at this season to 

 j)revail as far down as the lower part of California. In winter 

 and spring the land in California is cooler than the sea air, and is 

 quite cold enough to extract moisture from it. But in summer 

 and autumn the land is the warmer, and cannot condense the 

 vapours of water held by the air. So the same cause which 

 made it rain in Oregon now makes it rain in California. As the 

 sun returns to the north, he brings the calm belt of Cancer and 

 the north-east trades along with him ; and now, at places where, 

 six months before, the south-west winds were the prevailing 

 winds, the north-east trades are found to blow. This is the case 

 in the latitude of California. The prevailing winds, then, in- 

 stead of going from a warmer to a cooler climate, as before, 

 are going the opposite way. Consequently, if, under these 

 circumstances, they have the moisture in them to make rains of, 

 they cannot precipitate it. Proof, if proof were wanting that 

 the prevailing winds in the latitude of California are from the 

 westward, is obvious to all who cross the Eocky Mountains 

 or ascend the Sierra Madre. In the pass south of the Great 

 Salt Lake basin those west winds have worn away the hills and 

 polished the rock by their ceaseless abrasion and the scouring 

 effects of the driving sand. Those v^ho have crossed this pass 

 are astonished at the force of the wind and the marks there 

 exhibited of its geological agencies. Panama is in the region of 

 equatorial calms. This belt of calms travels during the year, 

 back and forth, over about 17° of latitude, coming farther north 

 in the summer, where it tarries for several months, and then 

 returning so as to reach its extreme southern latitude some time 

 in March or Apjil. Where these calms are it is always raining, 

 and the chart* shows that they hang over the latitude of Panama 

 from June to November ; consequently, from June to November 

 is the rainy season at J^anama. The rest of the year that place is 

 * Vide Trade-wind Chart (Maury's Wind and Current). 



