9 ▁published ▁his ▁Tre at ise ▁on ▁the ▁Clar inet ▁( B oe hm ▁System ), ▁which ▁became ▁a ▁standard ▁text ▁about ▁the ▁instrument . ▁ ▁His ▁bal let , ▁Dance ▁of ▁the ▁Tw enty - First ▁Century , ▁written ▁for ▁Cambridge ▁University ' s ▁Foot light s ▁Club , ▁was ▁premier ed ▁in ▁the ▁US ▁in ▁ 1 9 3 8 ▁on ▁an ▁N BC ▁broadcast . ▁ ▁He ▁had ▁appearances ▁on ▁the ▁BBC ▁in ▁ 1 9 4 0 ▁and ▁ 1 9 4 1 , ▁and ▁became ▁the ▁first ▁black ▁man ▁to ▁conduct ▁the ▁London ▁Phil harm onic ▁in ▁ 1 9 4 2 ▁at ▁a ▁concert ▁in ▁the ▁Royal ▁Albert ▁Hall , ▁London , ▁before ▁an ▁audience ▁of ▁ 7 , 0 0 0 . ▁In ▁September ▁ 1 9 4 5 ▁he ▁conducted ▁the ▁Berlin ▁Phil harm onic ▁at ▁the ▁inv itation ▁of ▁music ▁director ▁Leo ▁Bor ch ard , ▁performing ▁William ▁Grant ▁Still ' s ▁Af ro - American ▁Sym phony ▁before ▁Al lied ▁serv ic emen . ▁According ▁to ▁J . ▁A . ▁Rog ers , ▁that ▁same ▁year ▁Dun bar ▁" con duct ed ▁the ▁Con cert s ▁Col onne ▁of ▁Paris , ▁Con cert s ▁Pas del oup , ▁Or ch estre ▁National ▁de ▁France , ▁and ▁the ▁Con cert s ▁du ▁Conserv atoire ▁in ▁a ▁Festival ▁of ▁American ▁Music ▁in ▁Paris ▁for ▁which ▁he ▁received ▁super l ative ▁pra ise ▁from ▁the ▁French ▁press ▁and ▁leading ▁conduct ors ▁as ▁Claude ▁Del v inc