216 Mt teorologica I Phenomena in 



vary where the upper current descends. Places in the neighbour- 

 hood of the tropics lie, consequently, for a long time under the in- 

 fluence of the trade winds ; but, on the other hand, they are for a 

 time entirely free from them." These places have also a dry and a 

 wet season, but, with this essential difference, that the rain falls 

 there when the sun is at its lowest declination. These south-west- 

 erly winds bringing the rain in their train, come slowly down the 

 mountains from the higher regions of the atmosphere. We see 

 them clearly in the clouds which begin at the commencement of 

 October to conceal the point and the Peak of Teneriffe ; then they 

 descend lower and lower, till at last they lay themselves down on the 

 crest of the mountain, and reveal themselves by fearful storms. 

 Perhaps a week, sometimes more, passes before they reach the sea- 

 coast, where they remain raging for months, during which time the 

 Peak is covered with snow. In Algiers, the commencement of the 

 rainy season is earlier ; and, on account of the place being more out 

 of the track of the trade-winds, it lasts longer. In the south of 

 Italy, the rainy season shrinks into the compass of a month ; at the 

 Alps, it entirely disappears ; nor do we experience it here, where 

 it rains the whole year through, and most of all in summer. But 

 in Italy, also, the commencement of the rainy season, as well as the 

 end of it, is marked by storms, and the quantity of water which falls 

 is greatest in spring and autumn. Here, on the contrary, the ex- 

 tremes of spring and autumn meet in the height of summer. Our 

 rainy season, therefore, takes place, unfortunately just at the time 

 when we wish to visit our watering places. St John's day fixes our 

 fate ; according to the old saying, 



'• If it rains on the day of St John, 



Hope of fine harvest is over and gone." 



And in England, 



" If the first of July be stormy weather 

 'Twill rain more or less four weeks together.'' 



Well ! so it is, and we must try and be thankful that in our weather 

 the laws of nature are strictly observed, but still it is hard to bear. 

 Yet, heaven be praised, there is no rule without an exception. 



A slight consideration, only, of this matter will shew that the de- 

 scent of the upper currents cannot take place on the whole of the 

 outer limits of the trade winds at one and the same time, because the 

 trade wind itself must be compensated for by the air of the tempe- 

 rate zones. The air which consequently flows down in one place 

 into the temperate zones must be replaced at another place by an 

 upward current from thence that the equilibrium may be restored. 

 Thus the currents which flow over each other in the torrid zones flow 

 side by side in the temperate zones, and as they sometimes change 

 their relative position, the characteristic features of our weather de- 

 pend on this alternate displacement of the polar and equatorial cur- 



