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