Marie Curie studied the radiation of all compounds containing the known radioactive elements, including uranium and thorium, which she later discovered was also radioactive. She also found out that:
- you can exactly measure the strength of the radiation from uranium;
- the intensity of the radiation is proportional to the amount of uranium or thorium in the compound - no matter what compound it is;
- the ability to emit radiation does not depend on the arrangement of the atoms in a molecule; it must be linked to the interior of the atom itself - a revolutionary discovery!
When she realized that some uranium and/or thorium compounds had stronger radiation than uranium, she made the following hypothesis: there must be an unknown element in the compound which had a stronger radiation than uranium or thorium. Her work aroused the interest of her husband, Pierre Curie, who stopped his own research on crystals and joined the "detective work" with his wife. And Marie was proven right: in 1898 the Curies discovered two new radioactive elements: radium (named after the Latin word for ray) and polonium (named after Marie's home country, Poland).
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Under the Constitution, treaties with tribal nations are part of the supreme law of the land, establishing unique sets of rights, benefits and conditions for the treaty-making tribes who agreed to cede millions of acres of their homelands to the United States, in return for recognition of property rights in land
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Eric Hobsbawm, the Marxist British historian, wrote a book called The Short Twentieth Century. The 20th Century had been shorter than other centuries because it had begun in 1914 with the outbreak of the First World War and terminated of course early in November 1989 with the fall of the Berlin Wall. The problem however, and of course we historians we like problems, is that everybody knew what we had left behind with the fall of the wall, but nobody knew what we were heading towards. As Douglas Hurd, the British Foreign Secretary at the time, put it, “this was a system [the Cold War], this was a system under which we had lived quite happily for 40 years.” Or as Adam Michnik, again my Polish solidarity intellectual, put it “The worst thing about communism is what comes afterwards.” While our populations were in jubilation in front of the television screens or on the streets of Berlin, governments were, it has to be said, seriously worried about the implications of this unforeseen, uncontrolled and uncontrollable collapse of the Warsaw Pact and the communist system. Tom Wolf, the American author, at the time had a bestseller called the Bonfire of the Vanities and a British MP that I knew at the time famously rephrased that as the ‘bonfire of the certainties.’ All of the reference points with which we’d lived for half a century and which had organized our diplomacy, our military strategy, our ideology, were like as many props that were suddenly pulled from us.
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Supremacy Clause. a provision of the U.S. Constitution that states that the Constitution, federal laws, and treaties of the United States are the "supreme Law of the Land
<span>Part of the 1820 Missouri Compromise required that if Missouri was admitted as a slave state, __maine___ would be admitted as a free state.</span>
