If I move a block of stone into the green-wood sector of the bagua, will my children grow up to be dull? If I put my desk next to a window, will my thoughts become insipid? Where is the dragon sleeping? Practitioners of feng shui, the Chinese art of geomancy, worry about such things—and not least whether in calculating the most propitious placement of a building, the orientation should be to magnetic north or to true north.
North, to a proto-Indo-European traversing the steppes a few thousand years back, was simply the direction the left hand pointed in when one faced the rising sun, a position that changed throughout the year. Our notion of north is based on a finer but still inexact science, its core assumption that we live on a perfect orb that spins along at a uniform rate. We do not, and it does not. Still, true north is a geometric concept that posits a line, a meridian, wrapping neatly around the planet. Also called geodetic north, it is constant to the extent that, for our lifetimes, it points pretty much toward Polaris, our North Star for the next few thousand years.