History
After the discovery of radioactivity by Henri Becquerel in 1896, it was generally believed that atmospheric electricity, ionization of the air, was caused only by radiation from radioactive elements in the ground or the radioactive gases or isotopes of radon they produce. Measurements of ionization rates at increasing heights above the ground during the decade from 1900 to 1910 showed a decrease that could be explained as due to absorption of the ionizing radiation by the intervening air.
Read more about this topic: Cosmic Rays
Famous quotes containing the word history:
“Only the history of free peoples is worth our attention; the history of men under a despotism is merely a collection of anecdotes.”
—Sébastien-Roch Nicolas De Chamfort (1741–1794)
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“The history of every country begins in the heart of a man or a woman.”
—Willa Cather (1876–1947)