confederation of five, afterwards six, tribes, among
whom the leading place was taken by the Mohawks; their territory lay
inland in what is now New York State and the basin of the St. Lawrence.
Numbering some 25,000, they maintained their own against the hereditary
foes by whom they were surrounded; they took kindly to English and Dutch
settlers, but were hostile to the French, and in the wars of the 18th
century were allies of England against the French; their descendants,
about 12,000, in reservations in Canada and New York are a peaceful
people, have accepted English religion and culture, and have proved
themselves skilful and industrious agriculturists.

IRREDUCIBLE CASE, name given to a cubic equation which cannot be
solved by the rule of CARDAN (q. v.).

IRTISH, an enormous river of Western Siberia and chief tributary of
the Obi; its course from the Altai Mountains runs NW. through the
Siberian plains for 1200 m.; it is navigable almost all the way in
summer, and in winter it is a highway for sledge traffic; on its banks
stand Semipalatinsk, Omsk, and Tobolsk.

IRVING, EDWARD, a great pulpit orator, born in Annan, Dumfriesshire;
bred for the Scotch Church, became in 1819 assistant to Dr. Chalmers in
Glasgow, and removed in 1822 to the Caledonian Church, London, where he
attracted to his preaching the world of fashion as well as intellect in
the city, who soon grew tired of him and left him, after which he took to
extravagances which did not draw them back, and drew around him instead a
set of people more fanatical than himself, and whose influence over him,
to which he weakly yielded, infatuated him still more; the result was
that he was deposed from the ministry of the Church that sent him forth,
and became for a time the centre of an organisation which still exists,
in a modified form, and bears his name; he was the bosom friend in his
early days of Thomas Carlyle, and no one mourned more over his aberration
than he, for he loved him to the end. "But for Irving," he says, "I had
never known what the communion of man with man means. His was the freest,
brotherliest, bravest human soul mine ever came in contact with; I call
him on the whole the best man I have ever, after trial enough, found in
this world, or now hope to find. Scotland sent him forth," he says, "a
herculean man, but our mad Babylon wore him and wasted him with all her
engines, and it took her 12 years"; he died in Glasgow, aged 42, "hoary