Isaac Israel Hayes, an American explorer, born in Chester co., Pa., March 5, 1832. He was educated in Philadelphia, graduated M. D. at the university of Pennsylvania in April, 1853, and in May was appointed surgeon of the second Grinnell expedition to the Arctic ocean, under command of Dr. Kane, which he accompanied, returning with it in 1855. Some reminiscences of this expedition are given in his "Aretic Boat Journey" (Boston, 1860). He was convinced that there was an open sea around the north pole, and presented his views to the American geographical and statistical society in December, 1857, and during the ensuing winter in lectures on arctic explorations delivered in different parts of the country, especially at the Smithsonian institution in Washington. Subscriptions in aid of an exploring expedition were collected by scientific and other societies in America and Europe, and with this aid he was enabled to fit out the schooner United States, of 133 tons, in which he sailed from Boston, July 9, 1860, with a company of 14 persons besides himself.

He reached Upernavik, Greenland, Aug. 12, entered Melville bay on the 23d, and, after being twice driven back by the violence of the wind and floating floes of ice, anchored in Port Foulke on the W. coast of Greenland, in lat. 78° 17', Sept. 9. He explored the glacier system of Greenland, and after wintering in Port Foulke set out April 4, 1861, upon a boat and sledge journey across and up the sound. The party of 12 men and 14 dogs found it impracticable to drag the boat over the hummocks of ice, and sending it back, Dr. Hayes pressed onward with three companions and two dog sledges. They reached the W. coast of the sound May 10, and travelled north until the 18th. Their provisions being exhausted, they were obliged to return, having reached land in lat. 81° 37' N., beyond which they saw open water. The schooner was broken out of the ice July 10, and returned to Boston Oct. 23. In this expedition Dr. Hayes discovered a new sound or channel opening westward from the centre of Smith sound. He found the portion of Kennedy channel which Morton had reported to be open in June, 1854, frozen over May 23,1861, and the W. coast of the channel heaped with great masses of ice. Before his return home civil war had begun, during which he served as a surgeon in the U. S. army.

He published an account of the expedition under the title of "The Open Polar Sea" (Boston, 1867), and received for his discoveries a gold medal from the royal geographical society of London, and another in 18G8 from the geographical society of Paris. In 1869 he sailed in the steamer Panther in company with the artist William Bradford, exploring the southern coasts of Greenland, and published " The Land of Desolation " (New York, 1872). He has also published " Cast away in the Cold," a story (Boston, 1868). He is now (1874) preparing a history of maritime discovery, and still entertains the project of reaching the north pole by way of Smith sound.