figure was crooked, his limbs shrunken; his hair hung in dishevelled locks over his haggard countenance. His temper was irritable, his habits penurious and solitary. He was, however, blameless in morals and reverent in religion. His scientific achievements would probably have been more striking if they had been less varied. He originated much, but perfected little. His optical investigations led him to adopt in an imperfect form the undulatory theory of light, to anticipate the doctrine of interference, and to observe, independently of though subsequently to F. M. Grimaldi (1618–1663), the phenomenon of diffraction. He was the first to state clearly that the motions of the heavenly bodies must be regarded as a mechanical problem, and he approached in a remarkable manner the discovery of universal gravitation. He invented the wheel barometer, discussed the application of barometrical indications to meteorological forecasting, suggested a system of optical telegraphy, anticipated E. F. F. Chladni’s experiment of strewing a vibrating bell with flour, investigated the nature of sound and the function of the air in respiration and combustion, and originated the idea of using the pendulum as a measure of gravity. He is credited with the invention of the anchor escapement for clocks, and also with the application of spiral springs to the balances of watches, together with the explanation of their action by the principle Ut tensio sic vis (1676).
His principal writings are Micrographia (1664); Lectiones Cutlerianae (1674–1679); and Posthumous Works, containing a sketch of his “Philosophical Algebra,” published by R. Waller in 1705.
HOOKER, JOSEPH (1814–1879), American general, was born
in Hadley, Massachusetts, on the 13th of November 1814.
He was educated at the military academy at West Point (1833–1837),
and on graduating entered the 1st U.S. Artillery. In the
war with Mexico (1846–48) he served as a staff officer, and rose
by successive brevets for meritorious services to the rank of
lieutenant-colonel. In 1853 he left the service and bought a large
farm near Sonoma, Cal., which he managed successfully till
1858, when he was made superintendent of military roads in
Oregon. Upon the opening of hostilities in the Civil War of
1861–65, he sacrificed his fine estate and offered his sword to the
Federal Government. He was commissioned brigadier-general
of volunteers on the 17th of May 1861 and major-general
on the 5th of May 1862. The engagement of Williamsburg
(May 5th) brought him and his subordinate Hancock into
prominence, and Hooker received the soubriquet of “Fighting
Joe.” He was engaged at the battle of Fair Oaks, and did
splendid service to the Union army during the “Seven Days.”
In the campaign of Northern Virginia, under General Pope
(August 1862), he led his division with fiery energy at Bristoe
Station, Manassas and Chantilly. In the Maryland campaign
(September) he was at the head of the I. corps, Army of the
Potomac, forced the defile of South Mountain and opened the
way for the advance of the army. The I. corps opened the great
battle of the Antietam, and sustained a sanguinary fight with the
Confederates under Stonewall Jackson. Hooker himself was
severely wounded. He was commissioned brigadier-general
in the United States army on the 20th of September 1862, and
in the battle of Fredericksburg (q.v.), under Burnside, he commanded
the centre grand division (III. and V. corps). He had
protested against the useless slaughter of his men on that
disastrous field, and when Burnside resigned the command
Hooker succeeded him. The new leader effected a much-needed
re-organization in the army, which had fought many battles
without success. In this task, as in subordinate commands
in battle, Hooker was excelled by few. But his grave defects
as a commander-in-chief were soon to be obvious. By a well-planned
and well-executed flanking movement, he placed himself
on the enemy’s flank, but at the decisive moment he checked
the advance of his troops. Lee turned upon him, Jackson
surprised and destroyed a whole army corps, and the battle of
Chancellorsville (see Wilderness), in which Hooker was himself
disabled, ended in a retreat to the old position. Yet Hooker
had not entirely forfeited the confidence of his men, to whom
he was still “Fighting Joe.” The second advance of Lee into
Union territory, which led to the battle of Gettysburg, was
strenuously resisted by Hooker, who would have inflicted a
heavy blow on Lee’s scattered forces had he not been condemned
to inaction by orders from Washington. Even then Hooker
followed the Confederates a day only behind them, until, finding
himself distrusted and forbidden to control the movements of
troops within the sphere of operations, he resigned the command
on the eve of the battle (June 28, 1863). Faults of temper
and an excessive sense of responsibility made his continued
occupation of the command impossible, but when after a signal
defeat Rosecrans was besieged in Chattanooga, and Grant
with all the forces of the West was hurried to the rescue, two
corps of the Army of the Potomac were sent over by rail, and
Hooker, who was at least one of the finest fighting generals
of the service, went with them in command. He fought and won
the “Battle above the Clouds” on Lookout Mountain which
cleared the way for the crowning victory of the army of the
Cumberland on Missionary Ridge (see Chattanooga). And in
command of the same corps (consolidated as the XX. corps)
he took part in all the battles and combats of the Atlanta
campaign of 1864. When General McPherson was killed before
Atlanta, the command of Grant’s old Army of the Tennessee
fell vacant. Hooker, who, though only a corps commander,
was senior to the other army commanders, Thomas and Schofield,
was normally entitled to receive it, but General Sherman feared
to commit a whole army to the guidance of a man of Hooker’s
peculiar temperament, and the place was given to Howard.
Hooker thereupon left the army. He was commissioned brevet-major-general
in the United States army on the 13th of March
1865, and retired from active service with the full rank of major-general
on the 15th of October 1868, in consequence of a
paralytic seizure. The last years of his life were passed in the
neighbourhood of New York. He died at Garden City, Long
Island, on the 31st of October 1879.
HOOKER, SIR JOSEPH DALTON (1817– ), English
botanist and traveller, second son of the famous botanist Sir
W. J. Hooker, was born on the 30th of June 1817, at Halesworth,
Suffolk. He was educated at Glasgow University, and almost
immediately after taking his M.D. degree there in 1839 joined
Sir James Ross’s Antarctic expedition, receiving a commission
as assistant-surgeon on the “Erebus.” The botanical fruits of the
three years he thus spent in the Southern Seas were the Flora
Antarctica, Flora Novae Zelandiae and Flora Tasmanica, which
he published on his return. His next expedition was to the
northern frontiers of India (1847–1851), and the expenses in
this case also were partially defrayed by the government. The
party had its full share of adventure. Hooker and his friend
Dr Campbell were detained in prison for some time by the raja of
Sikkim, but nevertheless they were able to bring back important
results, both geographical and botanical. Their survey of
hitherto unexplored regions was published by the Calcutta
Trigonometrical Survey Office, and their botanical observations
formed the basis of elaborate works on the rhododendrons
of the Sikkim Himalaya and on the flora of India. Among
other journeys undertaken by Hooker may be mentioned those
to Palestine (1860), Morocco (1871), and the United States
(1877), all yielding valuable scientific information. In the midst
of all this travelling in foreign countries he quickly built up for
himself a high scientific reputation at home. In 1855 he was
appointed assistant-director of Kew Gardens, and in 1865 he
succeeded his father as full director, holding the post for twenty
years. At the early age of thirty he was elected a fellow of the
Royal Society, and in 1873 he was chosen its president; he
received three of its medals—a Royal in 1854, the Copley in
1887 and the Darwin in 1892. He acted as president of the
British Association at its Norwich meeting of 1868, when his
address was remarkable for its championship of Darwinian
theories. Of Darwin, indeed, he was an early friend and supporter:
it was he who, with Lyell, first induced Darwin to
make his views public, and the author of The Origin of Species
has recorded his indebtedness to Hooker’s wide knowledge and
balanced judgment. Sir Joseph Hooker is the author of numerous
