December 9

Thousands of freedpeople followed Sherman’s columns. At this creek General Jefferson C. Davis’s corps crossed and pulled up the pontoon bridge behind it, leaving them to Confederate cavalry. Many drowned trying to swim across.

Sixteen men set out with ten ponies, two dog teams and the motor party ahead. The ponies marched by night to rest in the warmth of the day. A blizzard pinned everyone below the Beardmore Glacier for four days from 5 December, eating into the food meant for the plateau.

At the foot of the Beardmore Glacier the last five ponies were shot, as planned, and the meat was cached for the return. From here the men hauled their own sledges.

Joffe, then Trotsky, played for time and for a revolution in Germany. General Max Hoffmann put the German terms on a map: Poland and the Baltic provinces were not coming back.

A four-part suite recorded in one evening with McCoy Tyner, Jimmy Garrison and Elvin Jones, and offered as thanks to God for the awakening that ended his addiction in 1957. In the last part, “Psalm”, Coltrane’s saxophone plays the words of the poem printed in the sleeve, syllable by syllable.

Douglas Engelbart, in one 90-minute session, showed the mouse, windows, hypertext, video conferencing and shared-screen editing. The computer was at SRI in Menlo Park, 50 km away, linked by leased lines and a microwave video relay, and the audience of about a thousand engineers had never seen a…

After two years with no case anywhere and searches in every country that had recently had smallpox, the Global Commission for the Certification of Smallpox Eradication signed its parchment certificate in Geneva.

Senators Joe Lieberman and Herb Kohl showed clips of Mortal Kombat’s fatalities and Night Trap and threatened to regulate. The industry answered with its own ratings body, the Entertainment Software Rating Board, in 1994; its age labels are still on every boxed game sold in North America.

At its farthest from the Sun, about 35 times Earth’s distance and beyond the orbit of Neptune, it crawled along at under a kilometre a second, then began to fall back.

Thirty-eight years of falling back towards the Sun, speeding up all the way. The comet should be visible again by eye in 2061.

Perihelion came on 9 February 1986, with the comet on the far side of the Sun from Earth: the poorest showing on record. Then it climbed out past the orbit of Neptune, slowing all the way.