In the street, the scene was extraordinary. A crowd of men had gathered on the steps of Federal Hall. They seemed to be in shock. He saw a fellow come out of the Exchange and burst into tears. An old broker he knew passed him and remarked, with a shake of the head: “Ain’t seen anything like this since the crash of 1907.”

But in 1907, old Pierpont Morgan had been there to save the day. Maybe his son Jack could do something? But Jack Morgan was on the other side of the Atlantic in England, for the shooting season. The courtly senior Morgan partner Thomas Lamont was in charge.

As if on cue, at that moment, a group of men went up the steps of 23 Wall Street, the House of Morgan. He recognized at once the heads of the greatest banks. Could they stop the rot?

It seemed they could. At one thirty that day, Richard Whitney, the president of the Stock Exchange and a broker for Morgan, walked calmly out of 23 Wall Street, went straight to the floor of the Exchange, and started buying. Big money, big stocks, at well above the asking price. The banks had given him $240 million to use if he needed, but he only had to use a fraction. With a great sigh of relief, the market began to calm down.

The godlike spirit of Pierpont Morgan had descended from Olympus to rule the street once more.

That night William attended a big meeting of brokers. Everyone agreed the panic was unnecessary. On Friday, and on Saturday morning, the market suffered no further crisis.

He spent the rest of the weekend quietly. On Sunday, Charlie came by for lunch. “Technically,” William told them, “this sell-off has left the market in better condition than it’s been in for months.” After that, asking Charlie to keep his mother company, he went for a walk in Central Park.

The truth was, he needed some time alone, to think.

What had really happened? The underlying problem, he reckoned, was that for the last few years, there had been too much cash in the stock market. Funnily enough, it wasn’t that everything was booming. Farming and commodity prices had been weak, so instead of investing in those traditional staples, people had been looking for gains in stocks. Cash flowed in; brokers, banks and other finance houses mushroomed. Even in the huge American economy, there weren’t really enough productive stocks for all this cash, so prices rose. And then, of course, giddy greed set in.

Small investors, who should have been putting some savings in solid stocks, were buying wildly. Out of the total population of a hundred and twenty million, two, maybe three million were in the market now. That was a hell of a lot. And more than half a million of these little guys were even buying on a ten percent margin—putting down only a hundred dollars for every thousand they invested, with finance houses lending them the rest. Respectable brokerage houses like his own were lending clients two-thirds of the funds to purchase stocks. Money pushed stock prices ever higher. You couldn’t lose. And not only stocks. William knew damn well that some of the banks were parceling up their worst Latin American debt and selling it to suckers as valuable bonds. So long as everything went up, nobody noticed.