And I also found many travel guidebooks of Britain, France, Germany and other European countries. I'm not sure if he had really visited those countries during his stay in Germany but it's really interesting to see those guidebooks published in the early 20th century.
Even nowadays it's not easy to live in foreign countries, or just visit them. I wonder how he felt in NY or Berlin in the days with little information about foreign countries... But he was in his twenties then and seemed to have vivid curiosity and energy. Maybe having such grandfather is one of the reasons why I've been always attracted to Western countries.