410 



it in the northern equinoctial zone, become at 

 once more active. The column of air, which 

 reposes on this zone, is saturated with vapours, 

 because it is no longer renewed by the polar 

 current. Clouds form in this air saturated and 

 cooled by the combined effects of radiation and 

 the dilatation of the ascending* ah\ This air 

 augments it's capacity for heat in proportion as 

 it rarifies. With the formation and collection of 

 the vesicular vapours, the electricity accumu- 

 lates in the higher regions of the atmosphere. 

 The precipitation of the vapours is continual 

 during the day. It generally ceases at night, 

 and frequently even before sunset. The showers 

 are regularly more violent, and accompanied 

 with electric explosions, a short time after the 

 maximum of the diurnal heat. This state of 

 things remains the same, till the Sun enters into 

 the southern signs. This is the commencement 

 of cold in the northern temperate zone. The 

 current from the North pole is then reestab- 

 lished, because the difference between the heat 

 of the equinoctial and temperate regions aug- 

 ments daily. The North-East breeze blows 

 with violence, the air of the tropics is renewed, 

 and can no longer attain the degree of satura- 

 tion. The rains consequently cease^ the vesicu- 

 lar vapour is dissolved, and the sky resumes all 

 it's clearness and it's azure tint. Electrical ex- 

 plosions are no longer heard ; doubtless because 



