[EXPLORERS]. NANSEN, FRIDTJOF (1861-1930). Cabinet photograph signed ("Fridtjof Nansen"), by Harry Vander Weyde, London (imprint on mount), n.d. [circa 1895]. 165 x 107 mm. (6½ x 4¼ in.) including mount, mount worn and chipped, some overall browning. A shoulder-length portrait of the Norwegian explorer and Nobel Peace Prize winner, signed on the lower mount -- ANDREWS, ROY CHAPMAN (1884-1960). Photograph inscribed and signed ("Roy Chapman Andrews"), n.p., n.d. [circa 1930]. 305 x 234 mm. (12 x 9¼ in.) including margins, minor wear at corners. A candid shoulder-length portrait of the American naturalist and explorer, inscribed on the lower portion of the image: "To Thomas Jefferson High School With the regards of Roy Chapman Andrews Gobi Desert, 1930" -- DU CHAILLU, PAUL BELLONI (1831-1903). Large cabinet photograph inscribed and signed ("P.B. Du Chaillu"), by Markham & Johnson, Brooklyn, N.Y. (imprint on mount), n.d. [circa 1880]. 201 x 105 mm. (7 15/16 x 4 1/8 in.) including mount, some wear at mount corners. A full-length standing portrait of the African explorer, inscribed on mount verso: "To my friend James H. Beckman P.B. Du Chaillu Nov 8 1880." (3)