《Scientific American Supplement, No. 795, March 28, 1891》 - 免费有声读物

The Scientific American may be the oldest continuously published periodical in the United States, having launched its first publication in 1845. It has been a mainstay of popular science with in-depth articles across a broad spectrum of scientific fields. In this supplement are short articles ranging through such topics as The Business End of the American Newspaper, Chicago as a Seaport, Alternate Current Condensers, Gaseous Illuminants. and much more. - Summary by Larry Wilson