Oct. 29, read off the tape

Each print gets a made-up ticker symbol, the year, and in the right-hand column how long ago it was, counted from today. Every date and figure was checked against the sources listed at the bottom.

1. LBNZ
   1675

   Leibniz writes ∫ for the first time

   Working in his private notes, Gottfried Wilhelm Leibniz starts using a stretched long s as the symbol for an integral, because he thought of integration as summing infinitely many tiny pieces. The world had to wait a while to see it: the sign first appeared in print in June 1686, in the journal Acta Eruditorum. It is still the sign every calculus student writes.

   ∫ = a tall “s” for sumin print: 1686
   351 yrago
2. DGIO
   1787

   Don Giovanni opens in Prague

   Mozart's opera, with a libretto by Lorenzo Da Ponte, premieres at Prague's National Theatre, today the Estates Theatre, with Mozart himself conducting. He had logged the score as finished only the day before, on October 28.

   finished: Oct. 28opened: Oct. 29
   239 yrago
3. HOOD
   1792

   A volcano gets an admiral's name

   Lt. William Broughton, part of Capt. George Vancouver's expedition, sights a snowy peak from the Columbia River and names it for the British admiral Samuel Hood. Mount Hood, Oregon's highest point, stands roughly 11,249 feet tall.

   ≈ 11,249 ft
   234 yrago
4. RDX
   1863

   Geneva agrees on a red cross

   A four-day conference in Geneva, organized by a committee of five that included Henry Dunant, wraps up by adopting resolutions for national societies to help wounded soldiers. They also chose a shared emblem for medical volunteers: a white armband with a red cross, the Swiss flag with its colors swapped.

   Oct. 26–2936 attendees
   163 yrago
5. SUEZ
   1888

   The Suez Canal is opened to all

   The Convention of Constantinople, signed by nine powers, promises that ships of every flag may pass through the canal in war and in peace. Britain held back its full agreement until 1904, when the treaty took effect.

   9 signatoriesin force: 1904
   138 yrago
6. DJIA
   1929

   Black Tuesday

   The day this page borrows its tape from. After a 12.8% drop on Monday, the Dow Jones Industrial Average fell another 11.73% to close at 230.07, on a record of roughly 16 million shares. The slide went on until July 1932, and the Dow did not regain its September 1929 closing high until November 1954.

   ▼ 30.57 ptsclose 230.07≈ 16M shares
   97 yrago
7. BALL
   1945

   Ballpoint pens go on sale in the U.S.

   Milton Reynolds' pen goes on sale at Gimbels on 32nd Street in Manhattan for $12.50 apiece, a steep price for a pen in 1945. About 5,000 shoppers turned up, and some 50 police officers were sent to manage the crowd.

   $12.50≈ 5,000 shoppers
   81 yrago
8. CLAY
   1960

   Cassius Clay's first pro fight

   At Freedom Hall in Louisville, the 18-year-old Olympic champion, later known as Muhammad Ali, beats Tunney Hunsaker, the police chief of Fayetteville, West Virginia, by unanimous decision over six rounds, taking every round. His purse: $2,000.

   6 rounds$2,000 purse
   66 yrago
9. EXPO
   1967

   Expo 67 closes in Montreal

   Canada's world's fair, themed “Man and His World,” ends a six-month run that began April 28. Total attendance: 54,991,806. Its most famous survivor is Moshe Safdie's stacked-box housing complex, Habitat 67, which people still live in.

   54,991,806 visits569,500 on day 3
   59 yrago
10. ARPA
    1969

    The first message on ARPANET

    At 10:30 p.m. Pacific time, UCLA student programmer Charley Kline tries to log in to a computer at the Stanford Research Institute. The SRI machine crashed after two letters. About an hour later it worked. The full story is just below.

    UCLA → SRIBoelter Hall 3420
    57 yrago
11. GASP
    1991

    The first close look at an asteroid

    On its way to Jupiter, NASA's Galileo spacecraft passes about 1,600 km from 951 Gaspra, an 18-by-10-by-9 km rock. It was the first asteroid ever visited by a spacecraft, and the best images resolve features about 54 meters across.

    ≈ 1,600 km pass18.2 × 10.5 × 8.9 km
    35 yrago
12. GLNN
    1998

    John Glenn goes back up, at 77

    Thirty-six years after he became the first American to orbit Earth, John Glenn launches on Space Shuttle Discovery's STS-95, at 2:19 p.m. Eastern, making him the oldest person to fly in space at the time. He was one of seven crew members, alongside Pedro Duque, the first Spaniard in space, and Chiaki Mukai. The launch was also broadcast live in the new ATSC HDTV standard, the first U.S. broadcast in that format.

    age 777 crewlanded Nov. 7
    28 yrago

Six pairs from today's tape. Pick the one that happened earlier. Some are closer than they look.