00326nam a22001097a 4500020001800000082002600018245001800044260006500062300003300127500002000160650003600180  a0-87044-701-7  aRef. 500.76 W629 198810aWhy on earth?  aWashington, D.C. :bThe National Geographic Society,cc1988.  a96 p. :bcol., ill. ; 28 cm.  aIncludes index.14aSciencevQuestions and answers.