-1859] WRITINGS OF JOSEPH HENRY. 307 



the Caribbean Sea, and describe a curve on the surface of 

 the earth almost precisely the same as that which would be 

 exhibited by the projection on a horizontal surface of the 

 path described by an atom of air in its ascent at the equator, 

 in its passage westward, and in gradually curving round 

 toward the east. Mr. Redfield has shown that these curves 

 in whatever longitude of the northern hemisphere the hur- 

 ricanes have occurred, are of precisely the same character. 



If it be admitted that the motive power of this violent 

 commotion of the atmosphere is due to the evolved heat of the 

 moisture of the air, it will follow that such storms will be most 

 frequent and of greatest intensity in portions of the earth 

 where the relative amount of moisture is greatest, and that 

 they will therefore be found in the greatest number in the 

 heated and moist air directly over the Gulf Stream. The 

 atmosphere over this area must be in the highest degree in 

 a state of tottering equilibrium, since the air rising from the 

 heated surface along the axis of the stream must be much 

 more highly charged with moisture than that on either side. 

 Observation and theory are here in accord. 



These storms sometimes overlap the eastern coast of the 

 United States and produce great destruction of property 

 along the seaboard, and frequently a loss of life and shipping 

 in the region of the Gulf Stream. 



Hurricanes of the same character are found in the south- 

 ern hemisphere, describing similar curves, which turn south 

 however from the equator round to the east, in an opposite 

 direction to that of the curves described by the hurricanes 

 of the northern hemisphere. The space to which we are 

 limited in this article precludes a more minute discussion 

 of the phenomena which have been observed, and the opin- 

 ions which have been adopted, in regard to these storms. 

 We may have an opportunity of resuming the subject on 

 some other occasion. 



In this paper we have endeavored to give an exposition 

 of the general principles of the meteorology of the United 

 States, reserving for a future report a more detailed account of 

 the climatology of its different portions. We have especially 



