ATMOSPHERIC PHENOMENA, 177 



pcurs became visible. Flashes of lightning were seen chap. xvi. 

 in the south, and at sunset Volta's electrometer rcgu- ^ hT^ , 

 larly displayed positive indications, the separation of tlie 

 pith-balls being from three to four lines. After the 

 26th of the latter month the electrical equilibrium of 

 the atmosphere seemed broken, although the hygrometer 

 still denoted great dryness. 



The following is an account of the atmospheric phe- Atmospheric 

 nomena in the inland districts to the east of the cordil- Plitnouiena. 

 leras of Merida and New Grenada, in the Llanos of 

 Venezuela, and the Rio Meta, from the fourth to the 

 tenth degree of north latitude, wherever the rains 

 continue from May to October, and consequently include 

 the period of the greatest heat, which is in July and 

 A-Ugust : — " Nothing can equal the purity of the atmo- 

 sphere from December to February. The sky is then 

 constantly without clouds, and should one appear, it ia 

 a phenomenon that occupies all the attention of the 

 inhabitants. The breeze from the east and north-east 

 blows with violence. As it always carries with it air of 

 the same temperature, the vapours cannot become visible 

 througli refrigeration. Towards the end of February 

 and the beginning of March, the blue of the sky is less Hamidity, 

 intense ; the hygrometer gradually indicates greater 

 humidity ; the stars are sometimes veiled by a thin 

 stratum of vapours ; their light ceases to be tranquil 

 and planetary ; and they are seen to sparkle from time 

 to time at the height of 20° above the horizon. At this 

 period the breeze diminishes in strength, and becomes 

 less regular, being more frequently interrupted by dead 

 calms. Clouds accumulate towards the south-east, ap- Clouds. 

 pearing like distant mountains with distinct outlines, • 

 From time to time they are seen to separate from the 

 horizon, and traverse the celestial vault with a rapidity 

 which has no correspondence with the feebleness of the 

 ■wind that prevails in the lower strata of the air. At 

 the end oi March the southern region of the atmosphere 

 is illuminated by small electric explosions, like phos- 

 phorescent gleams confined to a single group of vanours. 



