Products & Materials Portable pH Meter See allHide authors and affiliations Science 12 Oct 1973:Vol. 182, Issue 4108, pp. 193DOI: 10.1126/science.182.4108.193-a Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 182, Issue 410812 October 1973 Table of Contents Print Table of Contents Back Matter (PDF) Ed Board (PDF) Front Matter (PDF)