A native of Connecticut and a graduate in Medicine from Harvard, Pickering moved to Philadelphia in 1827 and became active in the Academy and served as the librarian from 1829-33. In 1838 he was appointed to the scientific corps of the U. S. Exploring Expedition. He wrote volume 15 of the Expedition's reports, the Races of Man and their Geographical Distribution.

This unpublished journal from the Academy's manuscript file covers that portion of the expedition from Madeira to the Hawaiian Islands. It contains approximately 1000 pages. Pickering comments in some detail upon many scientific aspects of the areas visited; topography and geology, climate, mammals, birds, fish, reptiles, mollusks, insects, crustacea, and especially upon the plants seen and collected, with lists of specimens. The areas discussed, in chronological order are, in Volume 1: Madeira, Cape Verde Islands, Rio Janeiro, Rio Negro, Terra del Fuego, Chili, Peru, Lord Howe's Islands, South East Australia, Norfolk Island, New Zealand, Auckland Islands and the Antarctic Continent. In Volume 2: Clermont-Tonnere, Coral Islands, King George's Islands, Water Land, Dean's Island, Aurora Island, Tahiti and Eimeo, Bellinghausen Island, Rosa Island, Navigator Islands, Wallis Island, Horn Island, Hunters Island, Tonga Islands, Feejee Islands and Hawaiian Islands.

A few records of species listed here have been printed. See Fowler, Henry W. Fishes of Fiji, Supplement, p. 563, publ. by Govt. of Fiji, Suva, 1959.