328 THEORY OF WINDS. 



1834, at New York. When Robertson, the aero- 

 naut, ascended in a balloon from Castle Garden, 

 the wind was from the east, which carried him 

 westward across the Hudson river. At an ele- 

 vation of about 4000 feet above the earth he 

 disappeared in a mist or cloud, when he met 

 with a counter current from the west, that brought 

 him back over the city, and landed him ten 

 miles to the eastward on Long Island. It was 

 quite evident that the canopy of clouds, which 

 overspread the city and country in the afternoon, 

 was condensed by the colder upper current from 

 the west. 



From the 7th until the 10th of July (1834,) the 

 heat was excessive, ranging from 86 to 96 F. 

 in the shade, while the wind was from the south- 

 east. On the 10th, about noon, the wind pre- 

 vailed from the west, condensing the vapour of 

 the heated air into floods of rain, attended with 

 violent thunder and lightning. It is thus that 

 a land wind, which usually brings fair weather, 

 causes precipitation, by meeting with a southern 

 wind saturated with aqueous vapour. It is highly 

 probable, that at all times when rain attends a 

 southern wind, and when the land temperature 

 exceeds that of the sea, precipitation is owing to 

 the prevalence of a colder upper current from 

 an opposite direction. 



What can be more impressive and sublime than 

 those great movements of the atmosphere, by 

 which the waters of the ocean are wafted over 



