On this day in stock market history...

"Prices of Stocks Crash in Heavy Liquidation; Total Drop of Billions" read the New York Times headline following a 6.3% drop in the Dow Jones Industrial Average (^DJI -0.11%) on Oct. 23, 1929. The stock market had peaked that September, and by the end of the trading day on Oct. 23 it had shed nearly 20% of its value. It was a frenetic day, with 2.6 million shares sold in the final hour on the way to an estimated $4 billion loss in market value, equal to about 4% of the national GDP. The Great Crash of 1929 had begun in earnest.

Eight days after predicting a "permanently high plateau" for stocks, economist Irving Fisher again made his bullish case amid increasingly frenzied pessimism on Oct. 23, 1929. At a gathering of the DC Bankers Association, he reasserted his belief that stock prices were not inflated as much as some bears believed. "Public speculative mania," said Fisher, was the biggest reason why prices had gone parabolic over the preceding year, trailing by far his leading explanation that a number of large mergers "have effected great economies and have therefore increased the profits of corporations to a great extent." Strangely, he also cited America's decade-old alcohol prohibition amendment as one reason for the bubble. Perhaps, having less money to spend on booze, Americans decided to buy stocks instead.

Other investors supported Fisher. The Times interviewed several leading bankers on Oct. 23, and their consensus was that "the market might easily be supported since the sound stocks had fallen to levels that made them attractive for investment."

The sudden drop also brought out the poets of Wall Street. H. I. Phillips penned several market-oriented nursery rhymes in response to the Oct. 23 drop, and they were published in The Washington Post. Here's a collection of three, for your amusement:

Jack Spocks would buy no stocks,
His wife no tips would play,
And that explains just why they both
Got three square meals a day.
Mary was a little lamb,
Who never seemed to know
The stock she ought to put away
And which one to let go.
She went to see her broker and
Said "help me, sir, I pray,"
But everything that he advised
Worked out the other way.
I had a little oil stock
No bigger than my thumb;
I bought it on a phone tip--
Oh Lord, but I am dumb!

Tragedy in Texas
On Oct. 23, 1989, a plastics plant owned by Phillips 66 (PSX -0.66%) -- then Phillips Petroleum -- exploded, "hurling chunks of metal and other debris miles away and creating a fireball visible for 15 miles," in the words of The Washington Post. The company reported 23 missing employees; all were later declared dead. Another 314 employees suffered injuries in the blast.

Phillips 66 lost some $1.4 billion from the accident, split nearly evenly between capital losses and lost business revenue. An Occupational Safety and Health Administration inquiry led to a rather paltry $4 million fine for Phillips 66. The small fine did not do enough to encourage the company to institute effective safety reforms. Subsequent explosions at the same plant in 1999 and 2000 resulted in another three deaths and 74 injuries. The plant remains open to this day, having survived Phillips 66's 2002 merger with Conoco (COP -0.43%), which retains the ConocoPhillips name despite a 2012 de-merger that spun Phillips 66 off as an independent company.

How Apple got its groove back
Steve Jobs pushed Apple (AAPL 1.27%) hard into the post-PC era when he unveiled the iPod to the world on Oct. 23, 2001. Analysts and tech industry insiders got a glimpse of what would become Apple's signature flair at an unveiling marketed as the debut of "a breakthrough digital device." Apple said it had "invented a whole new category of digital music player" that meant "listening to music will never be the same again."

Analysts weren't sure what to make of the iPod. Many were skeptical that its $399 price tag could compete with similar MP3 players such as the $249 Nomad Jukebox from Creative Labs. The market has long since proven those doubting analysts wrong. Creative Labs lost 70% of its value over the following decade on its native Singapore stock exchange, while Apple went on to post gains of more than 4,000%. By the end of 2011, Apple had sold more than 300 million iPods worldwide. At that point, Microsoft (MSFT 0.37%), which had attempted to enter the MP3 player market with the Zune in 2004, waved the white flag and announced it would discontinue its device.