Here is how Gaston Darboux described him in his 1913 tribute:
"Our colleague was far from displeased by the prospect of these trips abroad. He had acquired a taste for travel in childhood, and it may be said that he was among those who knew our planet best. I myself encountered him in many different places: London, Rome, Vienna, Budapest, Copenhagen, St. Louis in America, Philadelphia, New York, and Boston. […] Moreover, in our conversations, I never tired of admiring his sound common sense, his insight, and the marvelous balance of his mind. Though he was unrivaled in mathematics, we may safely say that he would have succeeded admirably in any career he might have chosen."
Poincaré with Gaston Darboux on the deck of La Savoie in 1904. He was traveling to the United States, where he would take part in the Congress of Arts and Sciences in St. Louis, Missouri.