Economists like to preach prudence,
but they do not always practise it.
Ibrahim Oweiss was a young economist in Egypt's Ministry of Industry
when he offered some frank advice to his bosses.
He warned against a suffocating overconcentration of industry in Cairo and Alexandria.
And he later criticised General Nasser's hollow boast
that Egypt made everything "from the needle to the missile" (it made neither well).
This incaution made it safer for him to leave the country in 1960,
and hard to return.
In 1974, as a professor at Georgetown University in Washington,
Oweiss turned his attention to another troublesome concentration of assets:
the dollars accruing to the Gulf's oil exporters faster than they could make use of them.
"I wish to introduce a new term: petrodollars,"
he said at a speech in March that year.
This ensured the word would always be associated with his name
(although it had also appeared in an earlier testimony by Peter Peterson,
a former American commerce secretary).
Petrodollars, originally viewed as a threat to America and other oil importers,
were later seen as the saviour of America's currency and a cornerstone of its financial might.
At the end of 1974 the Treasury Department agreed to let Saudi Arabia's central bank buy Treasury bonds in secret,