That remark prompted a rare rebuke from China in the form of an editorial from the state-run news agency, Xinhua, which said that the implication that “China has been extracting Africa’s wealth for itself is utterly wide of the truth.”

On her valedictory African tour as secretary of state, Mrs. Clinton is visiting a very different continent from the one she came to as first lady in the 1990s.

If a collection of more than 50 nations that is home to a billion people who speak thousands of languages could be said to have a narrative, until recently it was one dominated, fairly or not, by war, famine and misrule.

Those wars have, with a few notable exceptions, largely ended. Even Somalia, the very picture of a failed African state, has begun to turn around. Many of Africa’s democracies have grown stronger, even in adversity and despite setbacks in places like Mali.

On this trip, Mrs. Clinton has taken pains to visit countries that are exemplars of democratic success. She began in Senegal, where a longtime president voted out of power left office peacefully, and also visited Malawi, a nation that had begun to stifle under an autocratic president. His death was followed by an orderly transfer of power to his deputy, Joyce Banda, a political adversary who now gives Africa two female heads of state. Mrs. Clinton will stop in Ghana for the funeral of President John Atta Mills, whose deputy was sworn in peacefully without anyone batting an eye.

But the biggest change is economic. The growth rate for the continent has crept up, rivaling Asia’s overall growth at the height of the “tiger economy” era of the 1990s, and it could reach 7 percent by 2015, according to the United Nations Development Program. And it is not just oil. Some of the top performers, like Rwanda, Ethiopia and Zambia, have not a drop of the stuff.

As the World Bank concluded in a recent report, “Africa could be on the brink of an economic takeoff, much like China was 30 years ago, and India 20 years ago.”