196 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



The first scientific mention of this shower of meteorites was by Torrey and Barbour 1 in 1890 

 and was as follows: 



This large and brilliant meteor fell in northern Iowa on the afternoon of May 2, 1890, at 5.30 o'clock and was widely 

 observed throughout the adjoining country. It appears that the phenomenon was rather in the nature of a meteoric 

 shower judging by appearances and the fact that several complete meteorites of considerable size (10, 70, and 100 

 pounds) were found at long distances from each other with a number of smaller ones. The splendor of this great lumi- 

 nous ball, bright even in full sunlight; its fiery cometlike tail, 3° to 4° in length; and the long train of smoke lingering 

 behind it fully 10 minutes and plainly marking its course in the sky inspired all who saw it with awe. It is described 

 as sputtering through its course like fireworks. To the students who saw it enter the atmosphere it appeared to start a 

 few degrees below the zenith and to pass below the horizon to the north-northwest of this place, descending at an angle 

 of 50°. The meteoric shower covered an area 2 or 3 miles wide near Forest City, Winnebago County, Iowa, while one 

 meteorite, weighing 100 pounds, passed into Kossuth County. These meteorites belong to the stone class. Their most 

 notable feature is the large amount of metal contained in the fragments examined, it amounting to 45 per cent by weight. 

 The metal is in exceedingly small globules and thin flakes, making its separation from the matrix a matter of consider- 

 able difficulty. The specific gravity of the matrix was 2.63; of the metal free from matrix 5.75. 



Analysis gave: 



Si0 2 Fe 2 3 A1 2 3 CaO MgO 



47.03 29.43 2.94 17. 58 2.96 =99.94 



At the same time a study of the orbit of the meteorite was given by Newton 2 as follows: 



The newspaper accounts of the Iowa meteorite of May 2, 1890, are definite enough to give a fair idea of its orbit 

 around the sun before entering our atmosphere. The path that best satisfies the accounts that seem to be reliable was 

 directed from a point a little north of west and somewhat higher than the sun, the sun being about 20° high and due 

 west. The velocity of the meteorite may be safely assumed to have been greater than that of Encke's comet at distance 

 unity, and less than that belonging to a parabolic orbit. With this assumption the orbit would be inclined to the 

 ecliptic between 10° and 20° with direct motion. The ascending node is in longitude 42.5°. The body had passed 

 perihelion several weeks, how long depends mainly upon the inclination to the horizon of the path through the air. 

 The perihelion distance was probably between 0.50 and 0.70, this element also being largely dependent upon the same 

 inclination. 



In October of the same year a further account was given by Kunz 3 as follows: 



On Friday, May 2, 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 10 to 15 minutes; it was accompanied by a noise likened to that of heavy cannonading or thunder, and many 

 people rushed to their doors thinking it was the rumbling of an earthquake. Authentic reports of it came from Des 

 Moines, Mason City, Fort Dodge, Emmetsburg, Algona, Ruthven, Humboldt, Britt, Garnet, Grinnel, 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 meteorite fell. It exploded about 11 miles northwest of Forest City, at 

 Leland, Winnebago County, in the center of the northern part of Iowa, latitude 43° 15' N., longitude 93° 45' W. of 

 Greenwich, near the Minnesota State line, and the fragments were scattered over an area 1 mile wide and nearly 

 2 miles long. Masses weighing, respectively, 80, 66, and 10 pounds have been found, two of 4 pounds, and about 500 

 fragments weighing from 0.05 to 20 ounces each, while a part of the mass is believed to have passed over into Minnesota. 

 The pieces are all angular with rounded edges. 



The meteorite is a typical chondrite apparently of the type of the Parnallite group of Meunier. The stone is 

 porous, and when it is placed in water to ascertain its specific gravity, there is considerable ebullition of air. The 

 specific gravity on a 15-gram piece was found to be 3.638. The crust is rather thin, opaque black, not shining, and 

 under the microscope is very scoriaceous, resembling the Knyahinya (Hungary) and the West Liberty (Iowa) meteorites. 



A broken surface shows the interior color to be gray, spotted with brown, black, and white, containing small specks 

 of meteoric iron from 1 to 2 mm. across. Troilite is also present in small rounded masses of about the same size. On 

 one broken surface was a very thin scum of black substance, evidently graphite, soft enough to mark white paper; a 

 feldspar (anorthite) was likewise observed, as well as enstatite. 



Results and analyses furnished by L. G. Eakins. 



Approximate composition of the mass: 



Nickeliferous iron 19. 40 



Troilite 6.19 



Silicates soluble in HC1 36. 04 



Silicates insoluble in HC1 38. 37 



Analysis of the nickeliferous iron: 



Fe Ni Co P 



92.65 6.11 .65 trace =99.41 



Specific gravity of the mass, 3,804 at 28.5° Celsius. 



