) ▁of ▁Brazil . ▁In ▁the ▁second ▁half ▁of ▁the ▁ 1 7 th ▁century , ▁the ▁captain cy ▁population ▁grew ▁to ▁ 8 , 0 0 0 ▁inhabitants , ▁two - third s ▁of ▁whom ▁were ▁probably ▁African ▁slaves ▁and ▁Indians . ▁ ▁At ▁the ▁beginning ▁of ▁the ▁ 1 8 th ▁century , ▁Brazil ▁began ▁to ▁eng age ▁in ▁gold ▁and ▁diam ond ▁min ing , ▁which ▁brought ▁about ▁remarkable ▁changes ▁in ▁the ▁col ony ' s ▁economy ▁and ▁stim ulated ▁a ▁great ▁migration ▁from ▁Europe , ▁thereby ▁increasing ▁the ▁number ▁of ▁people ▁of ▁European ▁ancest ry . ▁The ▁former ▁village ▁became ▁a ▁town ▁of ▁ 2 4 , 0 0 0 ▁in ▁ 1 7 4 9 . ▁When ▁the ▁colonial ▁capital ▁was ▁transferred ▁from ▁Salvador , ▁Bah ia ▁to ▁Rio ▁de ▁Janeiro ▁in ▁ 1 7 6 3 , ▁the ▁town ▁expanded ▁farther , ▁far ▁beyond ▁its ▁walls . ▁The ▁remains ▁of ▁the ▁monument al ▁Roman - style ▁aqu ed uct ▁Ar cos ▁da ▁L apa ▁( L apa ▁Arch es ) ▁built ▁at ▁this ▁time ▁still ▁stand ▁in ▁the ▁city . ▁ ▁At ▁the ▁end ▁of ▁the ▁ 1 8 th ▁century , ▁the ▁town ' s ▁economy , ▁as ▁well ▁as ▁that ▁of ▁the ▁col ony ▁as ▁a ▁whole , ▁was ▁in ▁a ▁crisis ▁because ▁of ▁the ▁decl ine ▁of ▁the ▁mines ▁and ▁competition ▁from ▁Central ▁America ▁for ▁the ▁world ▁sugar ▁market . ▁In ▁ 1 7 9 6 ▁the ▁value ▁of ▁exports ▁from ▁Rio ' s