27 août

The Athenians had decided to sail away when the Moon was eclipsed on the night of 27 August 413 BCE. Nicias, “somewhat over-addicted to divination”, would not move until the thrice nine days the soothsayers asked for had passed. The trap closed.

A French cardinal, Jean de Bilhères, ordered “the most beautiful work of marble in Rome” for his tomb chapel at St Peter’s. It is the only work Michelangelo signed: Vasari says he cut his name on the Virgin’s sash after hearing visitors credit another sculptor.

Howe landed the largest force Britain had ever sent overseas and outflanked Washington in Brooklyn. Two nights later the army escaped across the East River in fog; New York stayed British until 1783.

Examining zinc blende from Pierrefitte in the Pyrenees in his private laboratory in Cognac, Paul-Émile Lecoq de Boisbaudran saw two new violet lines. Mendeleev claimed it as eka-aluminium and told him his density of 4.7 was wrong. Measured on purer metal it came to 5.9, as predicted.

James Wallis, Chief Officer of Police on Rodrigues, recorded reports “like the distant roars of heavy guns” from the east. They had crossed about 4,800 kilometres of the Indian Ocean, a journey of some four hours for sound.

Captain O. Sampson’s Norham Castle lay at the eastern entrance of the Strait, about 40 miles off, under falling ash. Winchester quotes his log: “So violent are the explosions that the ear-drums of over half my crew have been shattered.” The Royal Society’s report, which used Sampson’s account,…

Around 10 am pyroclastic flows, clouds of hot ash and steam, raced over the water at more than 100 kilometres an hour and up to 80 kilometres from the volcano, over Sebesi and Sebuku to the Sumatran coast, still hot enough to burn people. About 1,000 died around Ketimbang.

The air wave took about 8 minutes to cover the 160 kilometres to Batavia. Between 10:15 and 10:20 the pressure gauge on a gasometer at the city’s gasworks leapt off the top of its chart, and windows burst across the city.

Some time after 10 o’clock an immense wave flooded every shore of the Strait and carried away what was left of Merak, Tjaringin and Teluk Betung. At Merak the water climbed the hillsides to about 35 metres on Verbeek’s plan; at Teluk Betung it rose 22 metres.

Barographs from Europe to South America recorded the air wave as it spread from Krakatau, closed in on the far side of the world near Bogotá, and rolled back. Strachey found it passing many stations not fewer than seven times over about five days, four times outward and three times back: three and…

At 10:02 local time the largest explosion tore the island apart. It was heard 4,800 kilometres away on Rodrigues, and over an area of nearly a thirteenth of the Earth’s surface: the loudest sound in recorded history. Working back from barographs around the world, Richard Strachey put it at 02:56…

Verbeek timed the last of the four at 10:52; some accounts put a final collapse at 10:41. The volcano was now under the sea, and a rain of mud fell for a while within 100 kilometres of it.

At Tanjung Priok, the port of Batavia, the tide gauge drew almost a wall of water at 12:15 and a crest 2.3 metres high at 12:36, two and a half hours after the wave left the island. Tide gauges recorded it as far away as South Africa.

After Vladimir Lvov, a former minister, brought him what he took for Kornilov’s demand for full power, Kerensky sacked his commander-in-chief by telegram. Kornilov refused to go and accused him of lying.

Kerensky’s own cabinet, with socialists in the majority but the Kadets back in. It fell apart over the Kornilov affair.

Enrique Susini and three friends, all medical students, broadcast Wagner’s opera from the roof of the Teatro Coliseo to the few dozen receivers in Buenos Aires. Argentina celebrates the date as its Día de la Radiodifusión.

Heinkel He 178: the first jet flightHeinkel He 178

Erich Warsitz flew the He 178, powered by Hans von Ohain’s turbojet, for a few minutes over Rostock, five days before the war began. In Britain, Frank Whittle had patented a jet engine in 1930; his first aircraft flew in May 1941.

Wartime RAF photographs found by Michael Ward suggested a route from the Western Cwm. Shipton led a small party, with Ang Tharkay as sirdar and two New Zealanders who asked to join, one of them a beekeeper named Edmund Hillary. They forced a way nearly to the top of the Icefall.

Its twin, Mariner 1, was blown up minutes after launch on 22 July 1962 when its guidance failed. Its identical twin Mariner 2 became the first spacecraft to work at another planet, and found Venus far too hot for the jungles of science fiction.

The only time they met him, at his rented house in Bel Air. After an awkward start everyone picked up guitars and jammed; nobody recorded it. Lennon later said, “Before Elvis there was nothing.”

Found dead at his London home, aged 32, of an accidental overdose of sleeping pills. The band heard the news in Bangor, North Wales, where they had gone to learn meditation from the Maharishi Mahesh Yogi. Nobody replaced him as manager. I knew that we were in trouble then. — Lennon, 1970

The UN fact-finding mission on Myanmar called for its generals to be investigated for genocide against the Rohingya, and called Facebook “a useful instrument for those seeking to spread hate”. The same day Facebook removed the accounts of Senior General Min Aung Hlaing.