ARTICLE PDF ADDITIONAL INFORMATION The original article can be found online at https://doi.org/10.1038/106617a0 RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS

ARTICLE Erratum. _Nature_ 106, 650 (1921). https://doi.org/10.1038/106650b0 Download citation * Published: 01 January 1921 * Issue Date: 13 January 1921 * DOI:

https://doi.org/10.1038/106650b0 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently

available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative