Products & Materials Equipment News See allHide authors and affiliations Science 05 Oct 1956:Vol. 124, Issue 3223, pp. 646DOI: 10.1126/science.124.3223.646 Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 124, Issue 322305 October 1956 Table of Contents Print Table of Contents Back Matter (PDF) Ed Board (PDF) Front Matter (PDF)
