Book ReviewsScientific Books EARTH-CURRENT OBSERVATIONS IN THE GERMAN TELEGRAPH SYSTEM By W. G. CADY See allHide authors and affiliations Science 07 Feb 1902:Vol. 15, Issue 371, pp. 222-225DOI: 10.1126/science.15.371.222 W. G. CADYFind 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.