As the Tucson project enters its final days, our host takes viewers to Biosphere 2 in nearby Oracle. Site of two experiments in self-sustained living, Biosphere 2 is now part of Columbia University's earth sciences program, serving as a laboratory for research into the effects of so-called greenhouse gases thought to be causing global warming. At the house, the finishing coat of the re-stuccoing system is going on, as well as a water-based highly reflective and waterproof roof coating. We check out a termite control system that uses insect growth hormones rather than poison, then tour the Meigs' beautiful new kitchen, complete with mesquite cabinets, black concrete counters, and gleaming stainless-steel commercial-grade appliances. We find cabinetmaker Tom Klijian behind his new library shelves-cum-powder room door. On the final day, Richard Trethewey arrives to check out the master bath, with walk-in closet with custom shelving, whirlpool bath, separate toilet/bidet room and a mahogan