Three years ago, I blogged about a performance of John Cage’s “As Slow As Possible” — a piece of organ music that he intended to be played, uh, as slow as possible. The first-ever staging of the piece lasted 29 minutes. Now a group of Germans are taking it to a logical extreme: Their performance will last 639 years. Back in 2003, the only sound audible was the gentle wheeze of the organ’s bellows being inflated, a process that took 17 months.

But now the audible music is going, and the New York Times has a terrific piece about it today:

Like the imperceptible movement of a glacier, a chord change was planned for Friday. Two pipes were to be removed from the rudimentary organ (which is being built as the piece goes on, with pipes added and subtracted as needed), eliminating a pair of E’s. Cage devotees, musicians and the curious have trickled in to Halberstadt, a town about two and a half hours southwest of Berlin by train known as the birthplace of canned hot dogs and home to a collection of 18,000 stuffed birds.

“In these times, acceleration spoils everything,” said Heinz-Klaus Metzger, a prominent musicologist whose chance comments at an organ conference nine years ago sparked the project. “To begin a performance with the perspective of more than a half-millennium —it’s just a kind of negation of the lifestyle of today.”

Apparently they’re placing weights on the organ’s keys to keep the notes sounding, and they’ve rigged a solar-panel array to the organ’s power supply so that an electrical outage won’t stop the performance. This latter fact, is, of course, what’s so “Clock of the Long Now” about this performance: When you plan a project that’s going to last for 639 years, you have to really think ahead.

By my calculations, assuming my progeny continue to have progeny, my 60th great-grandchild will be around to hear the song end.