Phenomena and Causes of Had Storms. 7 



paratively warm, while the northerly wind coming from a point 

 which is four thousand feet above the same boundary of the empire 

 of frost, will have a degree of cold probably surpassing any with 

 which we are acquainted. We infer from our preliminary princi- 

 ples, that immediately on meeting, the watery vapor of the warmer 

 current would be frozen with an intensity corresponding to the tem- 

 perature of the colder current ; that the minute hail stones thus form- 

 ed, and endued with such excessive cold, would begin to descend, 

 and accumulate to a size proportioned to the intensity of the cold of 

 the original nucleus — to the space through which they descended — 

 and to the humidity of the lower sti-ata of the atmosphere ; that is, 

 the colder they were when they began to fall, the farther they fell, 

 and the more humid the air, the larger they would become. 



We have supposed a strong case, namely, that a wind from the tor- 

 rid zone is suddenly brought into contact with a wind coming directly 

 from a point far within the limits of perpetual frost, a concurrence of 

 circumstances which appears to be not improbable, and which appears 

 also sufficient to explain the most extraordinary phenomena of hail 

 storms. But since natural causes do not commonly operate in their 

 greatest possible energy, it is probable that hail storms usually result 

 from these causes acting under circumstances less favorable in vari- 

 ous degrees. We need not even suppose any thing more than that 

 the cold current instead of meeting with an opposite hot wind, mere- 

 ly mixes with the stationary air of the hotter climates in order to pre- 

 cipitate their moisture in the form of hail. In every minute descrip- 

 tion of a violent hail storm, however, we shall probably find mention 

 made of this common circumstance, that opposite and violent ivinds 

 met* hurrying on the clouds from opposite points of the compass. 

 Thus a writer in the American Journal of Science describing a vio- 

 lent storm that occurred in the state of New Jersey, adds, "I observ- 

 ed then, and have many times observed since, that hail is usually ac- 

 companied by contrary winds, which seem striving over our heads 

 for the mastery." And Beccaria recognises the same feature of 

 clouds congregated from opposite quarters. " While, says he, these 

 clouds are agitated with the most rapid motions, the rain generally 

 falls in greatest plenty, and if the agitation be exceedingly great, it 

 generally hails. "| 



" Clark in Am. Jour. II, 134. Beccaria on Elec. in Priestley, 341. 

 f Priestley, 341, Nich. Jour. XXIV, 111. 



