For those who have not recognized this excellent piece of work, you find a wealth of information in the book by Willem Mook and many others downloadable from the IAEA web site (http://www-naweb.iaea.org/napc/ih/volumes.asp). Willi -- ..................................................................... Willi A. Brand, Stable Isotope Laboratory [log in to unmask] Max-Planck-Institute for Biogeochemistry Beutenberg Campus Hans-Knoell-Str. 10, 07745 Jena, Germany Tel: +49-3641-576400 P.O.Box 100164, 07701 Jena, Germany Fax: +49-3641-577400 http://www.bgc-jena.mpg.de/ http://www.bgc-jena.mpg.de/service/iso_gas_lab/ GASIR 2005 in Jena, October 10-12: http://www.bgc-jena.mpg.de/service/iso_gas_lab/gasir2005/index.shtml .....................................................................