A chilly fog and a scent of sulfur floated in the air above the Kawah Putih (white crater) area, Ciwidey, Bandung regency, West Java. Light showers did not drive away the 30 or so people who were gathering around the rim of one of the four craters of Mount Patuha. “This is the tuff, a stone with hygroscopic or water-absorbing characteristics. Try it on your tongue...” said a doctor in geology from the Bandung Institute of Technology, Budi Bra