^f 



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 die intensity of die cold of 

 the original nucleus — to the space through which Uicy descended 

 and to the humidity of the lower strata of the atmosphere; tliat is, 

 tlie 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 hall storms usually result 

 from these causes acdng under circumstances less favorable in vari- 

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

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

 ly mixes with the stationary air of the hotter climat^^^ 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 icinds 

 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 heuds 

 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.''f 



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

 t Priestley, 311, Nich. Joun XXIV, 111. 



