THE ANALYSTTHE ANALYTICAL JOURNAL OF THE CHEMICALZSOCIETYh.EDITORIAL ADVISORY BOARD"Chairman: J. M. Ottaway (Glasgow, U.K.)R. Belcher (Birmingham, U.K.)E. Bishop (Exeter, U.K.)L. R. P. Butler (South Africa)"H. J. Cluley (Wembley, UX.)E. A. M. F. Dahmen (Thehletherlands)A. C. Docherty (Billinghan, U.K.)D. Dyrssen (Sweden)G. Ghersini (Italy)"P. Gray (Leeds, U.K.)R. Herrman (West Germany)J. Hoste (Belgium)M. T. Kelley (U.S.A.)H. V. Malmstadt (U.S.A.)G. W. C. Milner (Harwell, U.K.)G. H. Morrison (USA.)E. J. Newman (Poole, U.K.)"J. H. Knox (Edinburgh, U.K.)"J. N. Miller (Loughborough, U.K.)H. W. Nurnberg (West Germany)"G. E. Penketh (Wilton, U.K.)"T. B. Pierce (Harwell, U.K.)E. Pungor (Hungary)D. I. Rees (London, U.K.)P. H.Scholes (Middlesbrough, U.K.)S. Siggia (U.S.A.)A. A. Smales, O.B.E. (Thornaby, U.K.)A. Walsh, K.B. (Australia)T. S. West (Aberdeen, U.K.)* J . White head (Stockton-on- Tees,A. L. Wilson (Medmenham, U.K.)P. Zuman (U.S.A.)"W. H. C. Shaw (Greenford, U.K.)"D. Simpson (Thorpe-le-Soken, U.K.)"A. Townshend (Birmingham, U.K.)U. K, )"Members of the Board serving on The Analyst Publications CommitteeREGIONAL ADVISORY EDITORSDr. J . Aggett, Department of Chernistry, University of Auckland, Private Bag, Auckland, NEW ZEALAND.Professor L. Gierst, Universit6 I-ibre de Bruxelles, Facult6 des Sciences, Avenue F.-D. Roosevelt 50,Professor H. M. N. H. Irving, Department of Theoretical Chemistry, University of Cape Town, Ronde-Professor W. A. E.McBryde, Faculty of Science, University of Waterloo, Waterloo, Ontario, CANADA.Dr. G . Rossi, Chemistry Division, Spectroscopy Sector, CEC Joint Research Centre, EURATOM, lspraDr. 1. Rubegka, Geological Survey of Czechoslovakia, Kostelni 26, Praha 7, CZECHOSLOVAKIA.Professor J. RGZiGka, Chemistry Department A, Technical University of Denmark, 2800 Lyngby,Professor K. Saito, Department of Chemistry, Tohoku University, Sendai, JAPAN.Professor P. C. Uden, Departmtmt of Chemistry, University of Massachusetts, Amherst, Mass. 01 003B ruxelles, B ELGlU M.bosch 7700, SOUTH AFRICA.Establishment, 21 020 lspra (Varese), ITALY.DEN MARK.U.S.A.Published by The Chemical SocietyEditorial: The Director of Publications, The Chemical Society, Burlington House,London, W1 \I OBN. Telephone 01 -734 9864. Telex No. 268001Advertisements: Advertisement Department, The Chemical Society, Burlington House, Piccadilly,London, WIV OBN. Telephone 01 -734 9864Subscriptions (non-members): The Chemical Society, Distribution Centre, Blackhorse Road,Letchworth, Herts., SG6 1 HNVolume 104 No 1242 September 1979@ The Chemical Society 197