File:The American Museum journal (c1900-(1918)) (17539530863).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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28 THE AMERICAN MUSEUM JOURNAL is surrounded by an upcast ridge from one hundred and fifty to two hundred feet above the surrounding plain, and fragments of meteoric iron are numer- ous in the slopes of this ridge and on the plain outside. At some time in the past a huge meteoric mass fell and ex- cavated this enormous hole. The similarity of form and propor- tions between the Arizona Meteor Crater and lunar craters is very strik- ing and is strongly suggestive of the idea that the craters on the moon are the unobliterated records of innumera- ble giant impacts of meteoric masses; unobliterated because, though formed millions, if not billions, of years ago, the moon's surface is not subject to ero- sion, as the moon has no atmosphere— it never had an atmosphere, being too small to retain one. Consequently it preserves a record of all that has hap- pened to scar it during countless ages of past time. COLLECTIONS OF METEORITES IX THE AMERICAN MUSEUM The collection of meteorites in the Amer- ican Museum is large and varied, and exhib- its in a considerable number of specimens various features of which Dr. Thomson speaks in his paper. In one of the alcove windows on the east side of the hall of geology and invertebrate paliEontology of the Museum, there are a number of transparencies taken from photo- graphs of meteors in flight. These were made by Dr. E. E. Barnard at the Yerkes Observatory, Williams Bay, Wisconsin. The meteors are represented by long white streaks of light. In looking at these par- ticular photographs one should not lose sight of the fact that the meteor trail is within our atmosphere .and that the multi- tudes of stars which are also in evidence are millions upon millions of miles away. It is also interesting to note that the light streaks are not of a uniform width through- out. Instead of being spindle-shaped in outline as we might at first suppose, they are more like a series of elongated spindles or darts joined by attenuated bands of light. Does this imply that the elements of the air
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The iron meteorite has a very thin black crust, of metallic luster. The texture within remains un- altered by the fiery journey through the sky. On some iron meteorites peculiar crosslines, "Widman- statten lines," may be etched with a weak solution of nitric acid

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