. ▁ ▁In ▁his ▁Code x ▁Mas ud icus ▁( 1 0 3 7 ), ▁Al - B ir uni ▁the or ized ▁the ▁existence ▁of ▁a ▁land mass ▁along ▁the ▁vast ▁ocean ▁between ▁Asia ▁and ▁Europe , ▁or ▁what ▁is ▁today ▁known ▁as ▁the ▁Amer icas . ▁He ▁dedu ced ▁its ▁existence ▁on ▁the ▁basis ▁of ▁his ▁accurate ▁estim ations ▁of ▁the ▁Earth ' s ▁circum ference ▁and ▁Af ro - E uras ia ' s ▁size , ▁which ▁he ▁found ▁sp anned ▁only ▁two - fif th s ▁of ▁the ▁Earth ' s ▁circum ference , ▁and ▁his ▁discovery ▁of ▁the ▁concept ▁of ▁specific ▁gravity , ▁from ▁which ▁he ▁dedu ced ▁that ▁the ▁ge ological ▁processes ▁that ▁gave ▁rise ▁to ▁E uras ia ▁must ' ve ▁also ▁given ▁rise ▁to ▁lands ▁in ▁the ▁vast ▁ocean ▁between ▁Asia ▁and ▁Europe . ▁He ▁also ▁the or ized ▁that ▁the ▁land mass ▁must ▁be ▁inhab ited ▁by ▁human ▁be ings , ▁which ▁he ▁dedu ced ▁from ▁his ▁knowledge ▁of ▁humans ▁inhab iting ▁the ▁broad ▁north - s outh ▁band ▁stretch ing ▁from ▁Russia ▁to ▁South ▁India ▁and ▁Sub - S ah aran ▁Africa , ▁the or izing ▁that ▁the ▁land mass ▁would ▁most ▁likely ▁lie ▁along ▁the ▁same ▁band . ▁He ▁was ▁the ▁first ▁to ▁predict ▁" the ▁existence ▁of ▁land ▁to ▁the ▁east ▁and ▁west ▁of ▁E uras ia , ▁which ▁later ▁on ▁was ▁discovered ▁to ▁be ▁America ▁and ▁Japan ". ▁ ▁Tab ula ▁Roger iana ▁ ▁The ▁Arab ▁ge ograph er ,