 A few years later, with the addition of Henry's brother-in-law, Robert Bowne Minturn, the firm became Grinnell, Minturn & Company, whose operations were greatly expanded by its entry into the general shipping business.The company became one of the strongest and best known mercantile houses in New York City.Henry Grinnell retired in 1850, around the time that he became very interested in the fate of the lost Franklin Polar Expedition.