|
Thursday, August 18, 1875, pg. 5
ADVANCEMENT OF SCIENCE.
THE AMERICAN ASSOCIATION.
QUESTIONS NOT STRICTLY SCIENTIFIC--THE
ANCIENT MEN OF GREAT LAKES--COURSE
OF AN IOWA METEORITE--TIDES OF NEW-
YORK HARBOR--ARTS OF SUBSISTENCE--
ELECTION OF OFFICERS.
From our Special Correspondent.
DETROIT,
Mich., Monday, Aug. 16, 1875.
...
Prof. N. R. Leonard, of the State University at Iowa City, Iowa, gave the
following description of the path of a meteorite seen in Iowa County, exhibiting,
also, a fragment of it. This meteorite appeared on Feb. 12, 1875, about 10:15 P.M.,
passing from south-west to north-east. Its own brilliancy, and a very clear sky,
caused it to be seen 450 miles from south-west to north-east, and 250 miles from
east to west. The meteor appeared to change somewhat its shape, being first described
as an oblong, with a smooth front and streaming sparks and train behind, afterward
assuming the form of an elongated horse-shoe with the closed end to the front. In
this latter form it seemed to have a sort of flowing jacket of flame, between which
and the brilliant core, or central part, there was a very narrow dark space. The
meteor changed its color as it approached the earth, passing through the different
shades, from white to red, when it disappeared, leaving, for a brief space of time,
a dark cloud, as is usual in cases of detonating meteors. The noise accompanying
the fall was heard over a large extent of country, as much as 100 miles to south-west,
but only a short distance north of the place of its fall. Fragments were gathered
up in Iowa County, Iowa, over a district measuring four miles by seven, the large
pieces all to the north and small pieces to the southern end of the area. The largest
pieces weighed 74, 48, 43, and 21 pounds; many others from 8 to 15 pounds each,
making a total of 500 pounds so far as found. The pieces are most of them surrounded
entirely with a black coating. Some cases of fracture which evidently took place
in the air were pointed out in a specimen exhibited before the association. The
newly-exposed surface in such cases held what might be called a secondary coating,
quite distinguishable in the specimen exhibited from the coating of the other surfaces.
Another specimen exhibited showed plainly a radiated or streaked appearance, by
which the direction of the flow of smelted surface matter could be ascertained.
This specimen was also surrounded by a raised circlet, composed of molten particles
of nickeliferous iron. In a specimen not exhibited, a like circlet having been broken
across in falling, its place showed unusually large particles of iron. The path
was carefully computed, and the method of the computation was given. No mere estimates
were relied upon, but only such observations as could be subjected to instrumental
measurement, such as in cases where the meteor was seen to pass by or close to some
definite point upon some terrestrial object. The path was mapped out on the board,
and remarked upon as unusually low in the hemisphere, not far from a straight line
until near its close. At a distance of sixty-eight miles from the place where the
largest piece fell the height was fifteen miles ; at a distance of thirty-eight
miles, twelve ; at a distance of twenty-two miles, eight ; at a distance of two
miles, two. These numbers refer to the nearest whole number. The angle of the path
with the meridian was given as 18°, and its course could be entered on a State
map by drawing a line from about four miles east of Ottumwa to a point about six
miles east of Marengo. The velocity of the meteorite's motion varied very much,
according to data given by different observers, from three and one-half to ten miles
per second. It was thought that six or seven miles might probably be not far from
a fair estimate, but the essayist did not consider any one of the numbers given
as entirely trustworthy.
... |
|
Sunday, Dec. 24, 1893, pg. 5
Big Meteors that Fell in Iowa.
From The Des Moines (Iowa) State Register.
Two remarkable meteorites have fallen in Iowa within the last twenty years.
Feb. 12, 1875, an exceedingly brilliant meteor, in the form of an elongated horseshoe,
was seen throughout a region of at least 400 miles in length and 250 in breadth,
lying in Missouri and Iowa. It is described as "without a tail, but having
a flowing jacket of flame. Detonations were heard so violent as to shake the earth
and to jar the windows like the shock of an earthquake," as it fell about
10:30 P. M., a few miles east of Marengo, Iowa. The ground for the space of some
seven miles in length by two to four miles in breadth was strewn with fragments
of this meteor varying in weight from a few ounces to seventy-four pounds.
On May 10, 1879, a large and extraordinary luminous meteor exploded with
terrific noise, followed at slight intervals with less violent detonations, and
struck the earth in the edge of a ravine near Estherville, Emmet County, Iowa,
penetrating to the depth of fourteen feet. Within two miles other fragments were
found, one of which weighed 170 pounds and another 32 pounds. The principal mass
weighed 431 pounds. All the discovered parts aggregated about 640 pounds. The
one of 170 pounds is now in the cabinet of the State University of Minnesota.
The composition of this aerolite is peculiar in many respects; but, as in nearly
all aerolites, there is a considerable proportion of iron and nickel.
|
