From 1879 to 1881 he journeyed widely in southern and eastern Asia — from Ceylon he traveled through India to the Himalayas, then accompanied the British army in the midst of the Second Anglo-Afghan War. He studied the customs and languages of the inhabitants of the Malay Archipelago (mainly Borneo, Ceram and Sulawesi) as well as those of the natives of Formosa. He spent considerable time with the Ainu of Japan, and in 1881 traveled from Vladivostok through Manchuria, Mongolia and Siberia on his way back to Germany.