Speculation on the Composition of the Earth's Core - 1924
THE EARTH IS BUILT SOMEWHAT on the same principle as an old-fashioned metal-cored golf-ball around which are wrapt several layers of lighter material, ending in a thin surface crust.
The metal core is pure iron or an alloy of that metal with nickel, says a report of Drs. E. D. Williamson and L. H. Adams, scientists of the Carnegie Institution of Washington, to the Washington Academy of Sciences. We quote as follows from Science Service's Daily Science News Bulletin (Washington):
"Dr. Adams said it was possible that the inmost core of the earth might be gold, or platinum, or other metals heavier than iron, but that it was practically certain that the center of the earth was an irregular sphere of iron about 4,200 miles in diameter. From the outer edge of this core, which is not sharply defined, to the surface is about 1,800 miles, and this distance is divided into three layers. Next to the central iron core, Drs. Williamson and Adams relate, is a sort of mixed layer of iron and of rock, which extends with a gradually diminishing proportion of iron to within about 900 miles of the surface. Above this is a layer of rock resembling that found at the surface, but containing more magnesia and less silicates. Finally, there is the surface crust, about 35 miles thick, consisting essentially of the granitic rocks. All this insight into the earth's anatomy is afforded, the scientists say, through a study of the velocity of earthquake waves through the earth, mathematical considerations having to do with the mass of the earth as a whole, and a study of meteorites, whose average composition is believed to closely resemble that of the earth as a whole. For example, it is known that the density of the whole earth is about 5.52 times that of water, while the average density of the surface rocks is only 2.7. There must, therefore, be something heavier inside."
Source: The Literary Digest for January 5, 1924
The metal core is pure iron or an alloy of that metal with nickel, says a report of Drs. E. D. Williamson and L. H. Adams, scientists of the Carnegie Institution of Washington, to the Washington Academy of Sciences. We quote as follows from Science Service's Daily Science News Bulletin (Washington):
"Dr. Adams said it was possible that the inmost core of the earth might be gold, or platinum, or other metals heavier than iron, but that it was practically certain that the center of the earth was an irregular sphere of iron about 4,200 miles in diameter. From the outer edge of this core, which is not sharply defined, to the surface is about 1,800 miles, and this distance is divided into three layers. Next to the central iron core, Drs. Williamson and Adams relate, is a sort of mixed layer of iron and of rock, which extends with a gradually diminishing proportion of iron to within about 900 miles of the surface. Above this is a layer of rock resembling that found at the surface, but containing more magnesia and less silicates. Finally, there is the surface crust, about 35 miles thick, consisting essentially of the granitic rocks. All this insight into the earth's anatomy is afforded, the scientists say, through a study of the velocity of earthquake waves through the earth, mathematical considerations having to do with the mass of the earth as a whole, and a study of meteorites, whose average composition is believed to closely resemble that of the earth as a whole. For example, it is known that the density of the whole earth is about 5.52 times that of water, while the average density of the surface rocks is only 2.7. There must, therefore, be something heavier inside."
Source: The Literary Digest for January 5, 1924