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No. 105: May-Jun 1996

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A Picture Speaks Louder Than Words

We hardly need more than the accompanying drawing to amplify our brief item (in SF#103) on that remarkable 7th. Century Mayan suspension bridge at Yaxchilan, in Mexico. Its three spans stretched 600 feet. The wooden deck was 10 feet wide and was suspended by large-diameter hemp ropes - probably bundles of six 1-inch ropes, according to modern calculations. The towers of the two bridge piers were 35 feet across and built up from large, flat stones (4 x 4 feet) set in bedrock. European engineers did not build a larger bridge until 1377! The following reference contains much more information.

(O'Kon, James A.; "Bridge to the Past," Civil Engineering, p. 62, January 1995. Cr. S. Jones)

Mayan suspension bridge at Yaxchilan The precocious Mayan suspension bridge at Yaxchilan. Temples and other city buildings in background.

From Science Frontiers #105, MAY-JUN 1996. 1996-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987