LettersDiscussion and Correspondence COAL BALLS By A. C. Noé See allHide authors and affiliations Science 30 Mar 1923:Vol. 57, Issue 1474, pp. 385DOI: 10.1126/science.57.1474.385 A. C. Noé Find this author on Google Scholar Find this author on PubMed Search for this author on this site Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears above.