Tumas was also active in Lithuanian cultural life in Vilnius. He was a board member of the Lithuanian Scientific Society and gifted some of his personal book collection to its new library. He was also a member of the Lithuanian Art Society and participated in the cultural Rūta Society. In July 1910, Tumas traveled as a correspondent to the official opening of the Grunwald Monument in Kraków during the celebration of the 500th anniversary of the Battle of Grunwald. His critical article was published in the Ukrainian newspaper . He contrasted the celebration, attended by many dignitaries, with Estonian and Latvian Song Festivals and concluded that the Grunwald celebration did not sufficiently involve all social classes. The Polish press responded by attacking Tumas and accusing him of anti-Polish attitudes.