File:The American Museum journal (c1900-(1918)) (17973903609).jpg

Title: The American Museum journal
Identifier: americanmuseumjo17amer (find matches)
Year: c1900-(1918) (c190s)
Authors: American Museum of Natural History
Subjects: Natural history
Publisher: New York : American Museum of Natural History
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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COLLECTIONS OF METEORITES IN AMERICAN MUSEUM 31 panwion and coiitraetiou of the mass just as joint planes are developed in rocks of the earth's crust, or, that they were developed at the time of the fall by impact. The iron meteorites have a thinner crust or skin than the stone meteorites. The iron skin has a metallic luster and is not so black as the crust of the aerolite. The interior of these specimens, like the aerolites, was not affected by their passage through the zone of fire, the atmosphere, for their texture is unaltered up to the very skin. In some iron meteorites peculiar crosslines known as "Widmanstatten" or "Neumann lines" may be etched on a polished surface by a weak solution of nitric acid. For some time it was supposed that this was a sure way of identifying meteorites, but there are a num- ber of siderite meteorites in the collection which cannot be etched. Their outer sur- faces may be chiseled into a nose, rounded, or pitted, depending upon whether they turned over in their rapid flight. The most striking instance in the Museum of a pro- tuberance shaped in this manner by the compresse<l oxygen flame on a siderite, is the large Willamette, Oregon, specimen. The back side of the specimen is rough and deeply scarred, while the front has a rounded, pitted, and fluted surface. There is also in another one of the alcove cases on the east side of the hall of geology and invertebrate paleontology one of the tliree collections of material which have been gathered from Meteor Crater. This exhibit has been placed here through the courtesy of I'rineeton University, and of Mr. D. M. Bar- ringer, of Philadelphia. Another exhibit is at the United States National Museum, Washington, and a third one at the Crater itself, in Coconino County, Arizona. Some years ago a company was organized under the direction of Mr. Barringer, which surveyed the site and sank drill holes in the bottom of the Crater to depths greater than five hundred feet. The products of the drill- ing, samples of the sedimentary rock, meta- morphosed sandstone, shale balls, Canyon Diablo meteorites, and ejected rock frag- ments are on exhibition. A booklet written by Mr. Barringer containing a number of maps, photographs, and descriptive text accompanies the exhibit. On an average of once a week the Museum is called upon to examine supposed meteor- itic material, but in most instances we are obliged to tell the expectant visitor that his specimen is some other kind of rock. It should be noted that if the thin metallic skin or black crust is absent, the specimen is in all probability not a meteorite. Chester A. Reeds.
Text Appearing After Image:
Rear view of the Willamette meteorite to show the effects of the flames, whipped backward in the speed of the flight and the fierceness of the burning. This meteorite, now in Memorial Hall of the Amer- ican Museum, was found in Willamette Valley, near Oregon City, Oregon, November 9, 1906. (See the back of the cover for another view of this meteorite)

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