🚀 go-pugleaf

    1.  It's "Tales from the White Hart", by Clarke.

    2.  Noise-cancelling headphones were used on the Voyager round-the-world
	flight, but the units quit working partway through the flight.  The
	book on the Voyager project gives the maker, but I do not have the
	reference handy.  

    3.  Noise cancelling only works for small volumes of space, smaller than
	a wavelength.  Attempts to produce cancellation over a large space
	with a cancellation source located at a different point than the
	noise source will result in nulls at some points in space and
	twice the sound level at other points.  So headphones work, but
	large-area cancellation doesn't.

					John Nagle