Afullsolutionoftwo-dimensionalNavier-Stokesandenergyequationwasconductednumericallytoanalyzethenaturalconvectionofthehorizontalstripwithanadiabaticsubstrate.Themainfeaturesofsuchconvectionare:(i)theleadingandtrailingedgeeffect,(ii)thenon-boundarylayereffect,and(iii)thesideedgeeffect.Theresultsarecomparedwiththeboundarylayertheoryandexprimentaldata.