It rises, it falls, it's bought, it's sold. On how much of our fate does the dollar's height have hold?"DOWN AND DOWN I go, . . . loving the spin I'm in" might have been written by Harold Arlen and Johnny Mercer as an anthem for the dollar. As it spins down, cries of both glee and anguish are heard in the land, and economists scramble to offer explanations.Some of these experts are confessing confusion, as all--well, almost all--signs point to dollar strength. The latest jobs report shows that the economy is steaming ahead. The Fed has again raised interest...