Emmet County, Iowa

The fall of this meteorite is in all its attendant circumstances one of the most remarkable on record. I therefore visited the region, on my return to America some months after its fall, and saw the two large masses which are the main representatives. Several short notices have already appeared on the subject; among them, one each, by Professor Shepard, Professor Peckham and Professor Hinrichs; and in describing the physical and chemical characteristics of the original masses, I shall be obliged to repeat some details that have been brought out

Locality - The place of fall is near Estherville, Emmet County, Iowa, just on the boundary of the State of Minnesota, lat 43° 30', Ion. 94° 50', within that region of the United States which has become remarkable for falls of meteorites, and of which I gave an outline map in my article on " the three meteorites that fell at Rochester in Indiana, Cynthiana in Kentucky, and Warrington in Missouri, within the space of one month.

The State of Iowa has become particularly conspicuous in recent years as the landing place of these celestial messengers; and I now have under examination still another remarkable one with some peculiar physical characters, but about which I have not yet obtained the historic details.

The phenomena accompanying the fall were of the usual character, but on a grander scale. It occurred about five o'clock in the afternoon, under a clear sky, with the sun shining brightly. In some places the meteorite was plainly visible in its passage through the air, and looked like a ball of fire with a long train of vapor or cloud of fire behind it; and one observer saw it 100 miles from where it fell. Its course was from northwest to southeast. The sounds produced in its course are referred to as being "terrible" and "indescribable," as scaring cattle and terrifying the people over an area many miles in diameter. At first they were "louder than that of the largest artillery; these were followed by a rumbling noise, as of a train of cars crossing a bridge. The concussion when it struck the ground was sensible to many persons, and it is reported that the soil was thrown into the air at the edge of a ravine where the largest of the masses was found. Two individuals were within two or three hundred yards of the spots where the two larger masses fell.

There were distinctly two explosions. The first took place at a considerable height in the atmosphere, and several large fragments were projected to different points over an area of four square miles, the largest mass going farthest to the east Another explosion occurred just before reaching the ground, and this accounts for the small fragments found near the largest mass.

Impact with the earth - A remarkable fact connected with the fall, besides that of the local disturbance of the earth alluded to, is the depth to which the mass penetrated. Had the fall taken place during the night, I doubt if the largest fragment would have been found. It struck within 200 feet of a dwelling house, at a spot where there was a hole (previously made) six feet deep and over twelve feet in diameter, filled with water, and having a bottom of stiff clay. This clay was excavated to a depth of eight feet before the meteorite was discovered, and two or three days elapsed before it was reached. Its total depth below the general surface of the ground was hence fourteen feet

The second large mass was found embedded in blue clay about five feet below the surface, at a place two miles distant from the first The third of the three largest masses was not discovered until the 23d of February, 1880, more than nine months after the fall, and its locality was four miles from the first A trapper on the prairies, who had witnessed the original occurrence, observed a hole in a dried-up slough; on sounding it with his rat spear, he detected a hard body at the bottom, and on digging found the stone at a depth of five feet Some small fragments were doubtless detached when the large mass approached the ground, as they were discovered near to it. The fragments thus far obtained weighed respectively, 437, 170, 92 &1/2, 28, 10 & 1/2, 4 and 2 pounds.

Height and velocity - A railroad engineer who observed it before the report, estimated its height to be forty miles, but at the time of the explosion much less; from an imperfect computation, he considered its velocity to be from two to four miles per second.

External characters - The masses are rough and knotted like large mulberry calculi, with rounded protuberances projecting from the surface on every side; the black coating is not uniform, being most marked between the projections. These projections have sometimes a bright metallic surface, showing them to consist of nodules of iron; and they also contain large lumps of an olive-green mineral, having a distinct and easy cleavage, which is more distinct where the surface has been broken. The greater portion of the stony material is of a gray color, with this green mineral irregularly disseminated through it the two minerals are mixed under various forms; sometimes the green mineral is in small rounded particles intimately mingled with the gray, at other times it is in small cavities in minute crystalline fragments, without any distinct faces, and almost colorless. The masses are quite heavy and vary much in specific gravity in their different parts; but the average cannot be less than 4-5. When broken, one is immediately struck with the large nodules of metal among the gray and green stony substances, some of which will weigh 100 grams or more. In this respect this meteorite is unique, it differing entirely from the mixed meteorites of Pallas, Atacama, etc., or the known meteoric stones rich in iron; for in none of these has the iron this nodular character.

Another striking feature in the relation of the iron and stony matter is, that the larger nodules of iron appear to have shrunk away from the matrix; an elongated fissure of from one to three millimeters sometimes intervening, separating the matrix and nodules to the extent of one-half the circumference of the latter, and appearing as if the iron had contracted from the stony matrix during the process of cooling. There are numerous small cavities of various sizes, where there are not any iron nodules, and where the minerals appear more crystalline, indicating an irregular shrinkage during the consolidation.

The minerals. At first sight I expected to find more than two earthy minerals. The microscope gave, as with most meteoric stones, unsatisfactory results. I therefore tried to separate the stony minerals mechanically; the only mineral that I was enabled to obtain pure in sufficient quantity, has an olive green color, and occurs in masses of from one-half to one inch in size, having an easy cleavage, especially in one direction; this is proved to be olivine. The same mineral occurs also in minute rounded concretions in other parts of the meteorite; and minute, almost colorless crystalline particles in the cavities I take to be olivine. Nickeliferous iron, as already stated, is very abundant. Troilite exists in small quantity. Chromite was also found.

(The American Journal of Science, 1880)
Submitted by Cathy Danielson