1890.] NEW YORK ACADEMY OF SCIENCES. 201 



plete and satisfactory account presented of the cliemical pro- 

 cesses by which these serpentine rocks have been formed. 



Mr. George F. Kunz read his paper, illustrated by speci- 

 mens and photographs, on 



THE AEROLITES WHICH FELL MAY 2D, 1890, IN WINNEBAGO 

 COUNTY, IOWA. 



On Friday, May 2d, 1890, at 5:15 p.m., standard Western 

 time, a meteor was observed over a good part of the State of 

 Iowa. It is described as a bright ball of fire, moving from west 

 to east, leaving a trail of smoke which was visible for from ten 

 to fifteen minutes ; it Avas accompanied by a noise likened to 

 that of heavy cannonading or of thunder, and many people 

 rushed to their doors, thinking it was the rumbling of an earth- 

 quake. Substantiated reports have been received from Des 

 Moines, Mason City, Fort Dodge, Emmetsburg, Algonia, Ruth- 

 ven, Humboldt, Britt, Garnet, Grinnell, Sioux City, and Forest 

 City; the noise was also heard at Chamberlain, South Dakota. 

 Some of these places were distant more than a hundred miles 

 from the point where the meteor fell. It exploded about eleven 

 miles northwest of Forest City, at Leland, Winnebago County, 

 in the centre of the northern part of Iowa, latitude 43° 15', 

 longitude 93° 45' west of Greenwich, near the Minnesota State 

 line, and the fragments were scattered over an area one mile 

 wide and nearly two miles long. Up to the present time, there 

 have been found masses weighing respectively eighty pounds, 

 sixty-six pounds, and ten pounds, two of four pounds, and about 

 five hundred fragments weighing from one-twentieth of an ounce 

 to twenty ounces each, while a part of the mass is believed to 

 have passed over into Minnesota. The pieces are all angular, 

 with rounded edges. 



This meteor is a typical chondrite, apparently of the type of 

 the Parnallite group of Meunier. which fell February 28th, 1857, 

 at Parnallee, India. The stone is porous, and when it is placed 

 in water to ascertain its specific gravity there is a considerable 

 ebullition of air. The specific gravity, on a fifteen-gramme 

 piece, was found to be 3.638. The crust is rather thin, opaque 

 black, not shining, and, under tlie microscope, is very scorious, 

 resembling the Knyahinya (Hungary) and the West Liberty 

 (Iowa) meteoric stones. A broken surface shows the interior 

 color to be gray, spotted with brown, black, and white, the latter 

 showing the existence of small specks of meteoric iron from one 

 to two millimetres across. Troilitc is also present in small 

 rounded masses of about the same size. On one broken surface 



