Thanks to Henry Grunder for the tip. I found Percival Scientific on the Thomas Register Website. (Registration is required for use -- free and relatively painless). For those who had asked, Percival is in Boone, Iowa 50036; phone (515) 432-6501 fax (515) 432-6503. Thanks again, Henry! Eugene Dillenburg Geology Department The Field Museum FAX: 312-922-9566 Roosevelt Road at Lake Shore Dr. phone: 312-922-9410 ext. 293 Chicago, Illinois 60605 "It's not really food if it doesn't hurt." -- Bruce Elliott