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rents of azote start simultaneously from two barometrical 

 maximums towards one and the same minimum. These 

 two atmospherical forces coming into collision produce 

 a frightful aerial storm called in the language of physical 

 geography a hurricane, or if the area embraced is small 

 a whirl-wind or water spout. The ruinous effect of these 

 phenomena is known to every schoolboy, and every year 

 brings us fresh records of their disastrous power. 



An interesting picture of daily thunder and lightning 

 is presented by the pacific zone which stretches on both 

 sides of the Equator to a breadth of 200 or 300 versts, 

 and shifts with the sun's ecliptic. Every day with the 

 rising of the sun the barometer stands at a fair height 

 and the day starts with fine sunshiny weather, but about 

 eleven o'clock in the morning clouds begin to appear on 

 the horizon and gather up towards the zenith, a barome- 

 trical minimum is formed, and from midday a thunder- 

 storm commences. Towards evening the weather clears 

 up, the barometer again rises, the sun comes out and 

 sets in a cloudless sky. It is remarkable that these rains 

 and storms occur only over ocean spaces or such sur- 

 iaces of dry land as are covered with abundant vegeta- 

 tion. The term tropical forest is applicable to precisely 

 those wooded regions which lie within the tropic zone of 

 daily storms: in the steppes and deserts however, which 

 also lie within the tropic zone, daily storms are un- 

 known. 



In all this we see clearly the close tie connecting the 

 solar rays with the vegetation upon earth. Existing under 

 the direct influence of the scorching equatorial sunshine 

 the luxuriant tropical flora distils exceptional supplies of 

 hydro-oxygen, and the upward passage of these gases 

 is so vigorous that the wind ceases to be noticeable; the 

 atmosphere rises rapidly, and afterwards, according to 

 the exhaustion of vegetation, sinks to a minimum. The 

 azote thrown to such a height together with its vaporous 

 clouds rolls down on both sides of the Equator in the 

 direction of the newly formed minimums, on the heated 



