The use of refined petroleum as fuel, which began in the 1850s, freed hundreds of millions of people from the toil of centuries, gave hundreds of millions more a life of ease and plenty, and, by allowing great cities to feed themselves from every corner of the world, multiplied the population of the earth fivefold.

Up until the Depression, recession had a moral character: it was supposed to purge the body economic of the greed and excess that attends a business expansion.

What holds an Arab leader in power is a mixture of violence and prestige. Both President Assad and King Hussein were felt to have defended Arab interests against the world. That, in the end, is more important than what they wear on their head.

If good history is dispassionate history, it must naturally wait until the passions of the period subside.

There are signs that the age of petroleum has passed its zenith. Adjusted for inflation, a barrel of crude oil now sells for three times its long-run average. The large western oil companies, which cartellised the industry for much of the 20th century, are now selling more oil than they find, and are thus in the throes of liquidation.

The use of refined petroleum as fuel, which began in the 1850s, freed hundreds of millions of people from the toil of centuries, gave hundreds of millions more a life of ease and plenty, and, by allowing great cities to feed themselves from every corner of the world, multiplied the population of the earth fivefold.

Cause and effect, the riddle of all history, is a particular devil in financial history; and never more so than today, where entire classes of security are collapsing not on public exchanges and stock-tickers but because there are no markets to establish prices this side of nothing.