The US Department of Agriculture may have some usefulness. Projecting future prices isn't one of them. In 2005, it looked five years ahead and saw a bushel of wheat selling for $3.50. Last week, the price rose to more than twice that much.

Why? God himself is to blame. Not since 1880 has Russia been so dry. And not since Napoleon's invasion has Moscow suffered so much soot. The government banned wheat exports and prices shot up to their highest point in 51 years. In the curious way that one thing lead to another, Napoleon's Russian Campaign grew out of the French Revolution like a forest fire out of a careless barbecue. The revolution stirred up enemies on all France's frontiers. When Napoleon had finished with them all, he had to reach farther – all the way to the banks of the Moskva River – to get his fingers burnt.