Word: mendeleyeff
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Dates: during 1934-1934
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Until 1220 when Alchemist Albertus Magnus discovered arsenic, mankind knew only ten elements-carbon, sulphur, gold, silver, copper, iron, lead, tin, antimony and mercury. In the next 500 years alchemists discovered only bismuth, zinc and phosphorus. Then scientific chemistry began By 1900, before which time perspicacious Dmitri Ivanovich Mendeleyeff figured that there must be 92 elements on earth, no more, no less, chemists had isolated 83. Last discovery of a tangible element, which could be handled and weighed, occurred in 1926 when Professor B. Smith Hopkins of the University of Illinois found Element No. 61 among some rare earths...
...Professor Fermi's admiring colleagues reported that, after wiping away a flood of electrons, he had smashed a batch of neutrons upon a piece of uranium which weighed 92 atomic units. For 13½ min., while it sputtered electrons, the uranium weighed 93 units. According to the Mendeleyeff Table it had no scientific business weighing more than uranium. During that period, reasoned Professor Fermi, the substance must have been not uranium, but hypothetical Element...
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