University of Sheffield

    Rights and permissions

    Reprints and Permissions

    About this article

    Cite this article

    University of Sheffield. Nature 165, 553 (1950) doi:10.1038/165553b0

    Download citation

    Comments

    By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.