Proximate Causes of certain Winds and Storms. 231 



tions, magazines and newspapers, vast numbers of different accounts 

 of various substances having been carried to a distance by the wind, 

 whose transportation can be accounted for on no other supposition 

 than that of its vertiginous motion. Salt storms, in the neighborhood 

 of the sea, present no difficulty, if such a motion be admitted.* 



3. If the wind accompanying a thunderstorm, have a vertiginous 

 motion, the cause is apparent, of the coldness of the air during its 

 continuance, and after it ; of the condensation of the vapor and the 

 descent ot hail. Thunder is popularly said to cool the air and puri- 

 fy it — and no wonder, if it be attended with a thorough and intimate 

 mixture of the upper and lower strata of the atmosphere. The com- 

 ing on of a thunderstorm in New Haven is commonly determined by 

 the condition of the lower strata of the atmosphere in that place 

 the warmth and moisture of the air, or, in other words, the sultriness 

 of the day. It is a portion of the same vapor that gathers upon the 

 outside of a tumbler, that afterwards descends in rain or hail. How 

 is it condensed and frozen ? Plainly it must either be raised itself 

 mto tne region of eternal frost, or the air of that region must be 

 brought down to it, or both. We also see clearly why, except 

 amongst the mountains, there are no hailstorms in the equatorial re- 

 gions. The term of perpetual congelation is at such a distance from 

 the surface of the earth in those latitudes, that the gyratory move- 

 ment does not extend far enough into it, to produce any thing more 

 than the condensation of the vapor into drops of rain. We also get 

 clear of the difficulty of forming such vast hailstones as are sometimes 

 known to descend, and of which it is difficult to conceive how they 

 can bo generated during the simple fall of the original nucleus to the 

 ground. A nucleus may be first frozen. It may then be hurried 

 aloit, like Blanchard's dog, or the volcanic ashes of St. Vincent, and 

 maintained in the air, till, by continued accretions, it has grown to the 

 size observed. Their occasional slowness of descent may arise, in 

 party from their encountering an ascending current of air. They 

 sometimes fall rapidly. f The hailstones were from the size of pig- 

 eons' eggs to the weight of three ounces, with a circumference of 

 seven inches. " When they struck the ground, they would rebound 

 to the height of ten or twelve feet, and pass twenty or thirty before 



* See Dr. Beck's paper in the first Volume of this Journal. 



t See Lewis & Clarke's Travels Appendix, under date of June 27, 1805 



