A way of finding out how old volcanic rock is.
Potassium/argon dating
Fact of the Day
Frederick the Great always dressed in a threadbare military uniform. He considered a crown a useless hat which let the rain through.
Quote of the Day
"History is a set of lies agreed upon.
"
~ Napoleon
On This Day
1390 The first secular witch trial in Paris took place, when the well-known peasant divine Jehenne de Brigue was tried for concocting a potion to torment her husband. Her torture led to the trial of further women, and she was finally burnt at the stake in 1391.
1618 Sir Walter Ralegh, the famous poet, courtier, spy, and explorer - well-known for his search for El Dorado and for popularising tobacco in England - was executed on the orders of James I, for his crew's unauthorised attack on the Spanish outpost of Santo Tomé de Guayana. After his execution, Ralegh's embalmed head was given to Ralegh's wife, who allegedly kept it in a velvet bag until her own death twenty-nine years later.
1923 Turkey became a republic following the dissolution of the Ottoman Empire.
1929 Share prices on the New York stock exchange collapsed, finished the downward spiral that had begun in earnest on 24 October 1929. The Wall Street Crash and subsequent Great Depression had a significant effect on economies and politics across the world.
1938 The Munich Agreement was signed (technically early in the morning of 30th, but dated today). It gave the Sudetenland to Nazi Germany.
1941 The Babi Yar massacre began. Almost 34,000 Jewish men, women and children were shot in Ukraine.