Hayden.] ^'^'~> [May 20, 



Stated Meeting, May 20, 1870, 



Continued from page 385, 



The following commnnication, descriptive of the recent 

 hail storm of the 8th inst., was received from Mr. Hector Orr, 

 of Philadelphia. Mr. Trego, Prof. Cresson, Dr. Coates, and 

 Dr. Horn described the storm as thej saw it, and Judge Low- 

 rie compared its features with those of the great hail storm 

 at Pittsburg, which he saw Sep. 80, 1850. 



Philadelphia, May 17, 1870. 

 To the Secretary of the Amer. Phil. Soc. 



Sir: — I have not seen any scientific account of the Late fierce hail storm 

 of tlie 8tli inst. in print. I noticed tlie following points of fact connected 

 with it. 



The moon entered her first quarter at 10.34' A. M. that day. Wind 

 from sunrise onward was brisk from N. E. till noon; a light scud flying 

 quite low, some two points divergent from the surface current, and a 

 heavy upper stratum of cloud coming nearly from the South. Towards 

 noon the upper clouds showed signs of condensation, and by 2 P. M#, the 

 various currents ueemed to converge over the city. At this time the sun 

 and moon made nearly equal angles on either side of our naei'idian, both 

 planets being also well advanced towards the zenith. Rain began to fall 

 about 2.10', the wind then passing across the pole from N. E. to N. W." 

 For several minutes previous to the fall and at its commencement, the 

 electrical discharges were violent and frequent. 



The halting of the clouds directly over head happened within that pe- 

 riod of the day in which the sun develops the most heat, and the artificial 

 warmth always present over such a surface as that of the built-up part of 

 Philadelphia, joined to the solar influence, seemed to me sufficient to drive 

 the vapor suddenly upward almost perpendicularly. The concentration, 

 congelation and precipitation, v/ere thus all embraced in a period of thirty 

 miiuites. 



The demolition of glass shows the wind to have come from the N. W. 

 until the storm reached the line of Sixth street, when it became West, and 

 thus continued to the Delaware. The original breeze entirely spent itself 

 during the fall, for during the last seconds of it the tendency of the stones 

 was slightly from the S. E. — the storm centering itself on the' city plot. 



Yours, Very Respectfully, 



HECTOR GEE. 



Dr. Genth communicated a new discovery of rhodium gold 

 in San Doraino-o, and the results of recent examinations of 



