472 METEOROLOGY. 



Professor Espy collected a number of cases in Pennsylvania and other parts 

 of the eastern States, of examples of this remark'^.ble phenomenon. The only 

 explanation which appears to be sufficient to account for it, and particularly the 

 amount of water wliich falls, is that of a water-spout or rotatory motion of the 

 air, produced by the disturbance of the ordinary stable condition of the atmo- 

 sphere by the abnormal heating of the stratum next the earth, and the subse- 

 quent bursting- of this upward, in the form of an ascending vortex, carrying with 

 it all the vapor which the air may contain from a surrounding space of several 

 miles. 



The quantity of water which falls will depend upon the amount of vapor in 

 the atmosphere which has been drawn into the vortex. It should be recollected 

 that although the air may be very dry at a high temperature, yet it may con- 

 tain a much greater quantity of watcn* in the form of vapor than a damper 

 atmosphere at a lower temperature. Tims, at 70° of temperature the air, when 

 perfectly saturated, contains about eight grains of vapor to the cubic foot; at 

 90° it is capable of containing about 15 grains. From this it appears that the 

 capacit}^ for vapor increases very rajjidly with the temperature ; in the case 

 above cited an increase of 20° of temperature nearly doubles the capacity for 

 moisture, and consequently produces a character of extreme dryness. 



Although, at the same time, the air may contain a ver^- large amount of vapor 

 which, condensed by a diminution of temperature due to its increased elevation, 

 or perliaps by a colder stratum innnediately above, may be precipitated on a 

 single soot^ and thus give rise to the extraordinary effects above described. 



ACCOl'XT OF A METEORITE. 



By Abner Woodworth, Council Grove, Kansas, March, 1866. 



On the 7th of March, 1843, 1 left Paral, a town situated on the river Allende 

 Mexico, State of Chiluiahua, and, travelling some 25 miles, course 15° east of 

 south, passed a lump of solid malleable iron, shape or figure resembling two 

 inverted saucers, one-third or more buried in the ground, supposed to weigh 

 five or six thousand pounds. It is softer than bar iron. The blacksmith at 

 Rio Florido cuts oti" pieces with his cold chisel for horseshoes. It lies upon a 

 level plain, 20 miles from any mountain. 



ACCOUNT OF A METEORITE. 



By Eobert Simson. 



Shortly before aniving at El Valle, on the road from Rio Florido, we encoun- 

 ter first streaks of iron — grateful to the lips and hands, cracked and sore with 

 the lime through which we have for some time been travelling, (going north- 

 ward.) The hill-sides, where bare, now show a reddish color; and vegetation 

 is not so luxuriant as heretofore. 



About hall'-way between El Valle and Parral, on a liend of the Rio Florido, 

 at a place called Concepcion, is a most splendid specimen of meteoric iron. It 

 is four feet above ground, and almost pure in quality. It is from two to three 

 feet one way, by, probably, two to five feet the other, very regular in shape, 

 and, where worn by the rubbing of hands, &c., of passers by, is^ bright, and, to 

 all appearance, is nearly pure metal. The steel hatchet cuts into it easily, but 

 with our means at hand we found it impossible to detach any part of it. It 

 stood at the corner of the house, apparently to guard it from collisions of wagons 



