Proximate Causes of certain Winds and Storms. 255 



The peculiarities of thunderstorms, (under which hailstorms, 

 lately the subject of a learned and accurate paper in the Journal, are 

 included as a particular case of a more general phenomenon,) are 

 probably less strongly marked on the eastern than on the western 

 side of the Atlantic. It niay be stated as one ground of this opin- 

 ion, that they do not seem to have attracted the attention of Eu- 

 ropean poets, either ancient or modern, as copious sources of illus- 

 tration and imagery ss strongly as was to have been expected, had 

 they often presented that succession of striking appearances which 

 is witnessed in the United Stales. It is not recollected that there is 

 to be found elsewhere in poetry, as accurate a description of the 

 commencement and progress of a thunderstorm, as is furnished by 

 President Dwight's Conquest of Canaan ; and though intended to be, 

 as it probably is, a correct account of this meteor as it occurs in the 

 land of Judea, the author doubtless copied from those impressions, 

 which nature herself had made upon his own imagination and mem- 

 ory. The lime of its comraencment and the direction of its motion, 

 are clearly indicated in the first four lines. 



" Long rush'd the victors o'er th' cnsanguin'd field, 

 " And scarce were Gibeon's lofty spires beheld, 

 " When tip the west dark clouds were seen to rise, 

 " Sail'd o'er the hills and lengthen'd round llie skies." 



(a.) Such persons as have paid any attention to the changes of 

 the weather in this country, must be well aware that our thunder- 

 storms begin in the after part of the day, and move from west to east. 

 They somedmes occur at night, but seldom after midnight. The 

 direction of their motion does not appear to depend upon the pre- 

 dominance of the westerly over the easterly winds, being much more 

 constant and uniform than that predominance, but to be a result and 

 a proof of a commotion, excited in the atmosphere at the time of their 

 formation, and of a rush of the air from the west towards the east, 

 in consequence of some new impulse just then communicated. 



(b.) The author of the article "Thunder," in the Encyclopedia 

 Perthensis, states, that along the eastern side of the island of Great 

 Britain, it is more frequent in the month of July than at any other 

 time of the year, Avhich he attributes to the circumstance that a wind 

 from the west then succeeds to the east wind that had prevailed from 

 April till the end of June. " For the most part however the west 



