|
See also:HELMHOLTZ, See also:HERMANN See also:LUDWIG See also:FERDINAND VON (1821-1894) , See also:German philosopher and See also:man of. See also:science, was See also:born on the 31st of See also:August 1821 at See also:Potsdam, near See also:Berlin. His See also:father, Ferdinand, was a teacher of See also:philology and See also:philosophy in the gymnasium, while his See also:mother was a Hanoverian See also:lady, a lineal descendant of the See also:great Quaker See also:- WILLIAM
- WILLIAM (1143-1214)
- WILLIAM (1227-1256)
- WILLIAM (1J33-1584)
- WILLIAM (A.S. Wilhelm, O. Norse Vilhidlmr; O. H. Ger. Willahelm, Willahalm, M. H. Ger. Willehelm, Willehalm, Mod.Ger. Wilhelm; Du. Willem; O. Fr. Villalme, Mod. Fr. Guillaume; from " will," Goth. vilja, and " helm," Goth. hilms, Old Norse hidlmr, meaning
- WILLIAM (c. 1130-C. 1190)
- WILLIAM, 13TH
William See also:Penn. Delicate in See also:early See also:life, Helmholtz became by See also:habit a student, and his father at the same See also:- TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
- TIME, MEASUREMENT OF
- TIME, STANDARD
time directed his thoughts to natural phenomena. He soon showed mathematical See also:powers, but these were not fostered by the careful training mathematicians usually receive, and it may be said that in after years his See also:attention was directed to the higher See also:mathematics mainly by force of circumstances. As his parents were poor, and could not afford to allow him to follow a purely scientific career, he became a surgeon of the Prussian See also:army. In 1842 he wrote a thesis in which he announced the See also:discovery of See also:nerve-cells in ganglia. This was his first See also:work, and from 1842 to 1894, the See also:year of his See also:death, scarcely a year passed without several important, and in some cases See also:epoch-making, papers on scientific subjects coming from his See also:pen. He lived in Berlin from 1842 to 1849, when he became See also:professor of See also:physiology in See also:Konigsberg. There he remained from 1849 to 1855, when he removed to the See also:chair of physiology in See also:Bonn. In 1858 he became professor of physiology in See also:Heidelberg, and in 1871 he was called to occupy the chair of physics in Berlin. To this professorship was added in 1887 the See also:post of director of the physico-technical See also:institute at See also:Charlottenburg, near Berlin,
and he held the two positions together until his death on the 8th of See also:September 1894.
His investigations occupied almost the whole See also:- FIELD (a word common to many West German languages, cf. Ger. Feld, Dutch veld, possibly cognate with O.E. f olde, the earth, and ultimately with root of the Gr. irAaror, broad)
- FIELD, CYRUS WEST (1819-1892)
- FIELD, DAVID DUDLEY (18o5-1894)
- FIELD, EUGENE (1850-1895)
- FIELD, FREDERICK (18o1—1885)
- FIELD, HENRY MARTYN (1822-1907)
- FIELD, JOHN (1782—1837)
- FIELD, MARSHALL (183 1906)
- FIELD, NATHAN (1587—1633)
- FIELD, STEPHEN JOHNSON (1816-1899)
- FIELD, WILLIAM VENTRIS FIELD, BARON (1813-1907)
field of science, including physiology, physiological See also:optics, physiological See also:acoustics, See also:chemistry, mathematics, See also:electricity and See also:magnetism, See also:meteorology and theoretical See also:mechanics. At an early See also:age he contributed to our knowledge of the causes of putrefaction and See also:fermentation. In physiological science he investigated quantitatively the phenomena of See also:animal See also:heat, and he was one of the earliest in the field of animal electricity. He studied the nature of See also:muscular contraction, causing a muscle to See also:record its movements on a smoked See also:glass See also:plate, and he worked out the problem of the velocity of the See also:nervous impulse both in the motor nerves of the See also:frog and in the sensory nerves of man. In 1847 Helmholtz read to the See also:Physical Society of Berlin a famous See also:paper, Uber See also:die Erhaltung der Kraft (on the conservation of force), which became one of the epoch-making papers of the See also:century; indeed, along with J. R. See also:Mayer, J. P. See also:Joule and W. See also:Thomson (See also:Lord See also:Kelvin), he may be regarded as one of the founders of the now universally received See also:law of the conservation of See also:energy. The year 1851, while he was lecturing on physiology at Konigsberg, saw the brilliant invention of the ophthalmoscope, an See also:instrument which has been of in-estimable value to See also:medicine. It arose from an See also:attempt to demonstrate to his class the nature of the glow of reflected See also:light sometimes seen in the eyes of animals such as the See also:cat. When the great ophthalmologist, A. von See also:Grafe, first saw the fundus of the living human See also:eye, with its optic disc and See also:blood-vessels, his See also:face flushed with excitement, and he cried, " Helmholtz has unfolded to us a new See also:world!" Helmholtz's contributions to physiological optics are of great importance. He investigated the See also:optical constants of the eye, measured by his invention, the ophthalmometer, the radii of curvature of the crystalline See also:lens for near and far See also:vision, explained the mechanism of See also:accommodation by which the eye can See also:focus within certain limits, discussed the phenomena of See also:colour vision, and gave a luminous See also:account of the movements of the eyeballs so as to secure single vision with two eyes. In particular he revived and gave new force to the theory of colour-vision associated with the name of See also:- THOMAS
- THOMAS (c. 1654-1720)
- THOMAS (d. 110o)
- THOMAS, ARTHUR GORING (1850-1892)
- THOMAS, CHARLES LOUIS AMBROISE (1811-1896)
- THOMAS, GEORGE (c. 1756-1802)
- THOMAS, GEORGE HENRY (1816-187o)
- THOMAS, ISAIAH (1749-1831)
- THOMAS, PIERRE (1634-1698)
- THOMAS, SIDNEY GILCHRIST (1850-1885)
- THOMAS, ST
- THOMAS, THEODORE (1835-1905)
- THOMAS, WILLIAM (d. 1554)
Thomas See also:Young, showing the three See also:primary See also:colours to be red, See also:green and See also:violet, and he applied the theory to the explanation of colour-See also:blindness. His great work on Physiological Optics (1856—1866) is by far the most important See also:book that has appeared on the physiology and physics of vision. Equally distinguished were his labours in physiological acoustics. He explained accurately the mechanism of the bones of the See also:ear, and he discussed the physiological See also:action of the cochlea on the principles of sympathetic vibration. Perhaps his greatest contribution, however, was his attempt to account for our See also:perception of quality of See also:tone. He showed, both by See also:analysis and by See also:synthesis, that quality depends on the See also:- ORDER
- ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
- ORDER, HOLY
order, number and intensity of the over-tones or harmonics that may, and usually do, enter into the structure of a musical tone. He also See also:developed the theory of See also:differential and of summational tones. His work on Sensations of Tone (1862) may well be termed the principia of physiological acoustics. He may also be said to be the founder of the fixed-See also:pitch theory of vowel tones, according to which it is asserted that the pitch of a vowel depends on the resonance of the mouth, according to the See also:form of the cavity while singing it, and this independently of the pitch of the See also:note on which the vowel is sung. For the later years of his life his labours may be summed up under the following heads: (1) On the conservation of energy; (2) on hydro-See also:dynamics; (3) on electro-dynamics and theories of electricity; (4) on meteorological physics;
(5) on optics; and (6) on the abstract principles of dynamics.
In all these See also:fields of labour he made important contributions to
science, and showed himself to be equally great as a mathe-
matician and a physicist.
He studied the phenomena of See also:electrical
oscillations from 186o to 1871 ,and in the latter year he announced
that the velocity of the See also:propagation of electromagnetic See also:induction
was about 314,000 metres per second. See also:Faraday had shown that
the passage of electrical action involved time, and he also
asserted that electrical phenomena are brought about by changesin intervening non-conductors or See also:dielectric substances. This led Clerk See also:Maxwell to See also:frame his theory of electro-dynamics, in which electrical impulses were assumed to be transmitted through the See also:ether by waves. G. F. See also:Fitzgerald was the first to 'attempt to measure the length of electric waves; Helmholtz put the problem into the hands of his favourite See also:- PUPIL (Lat. pupillus, orphan, minor, dim. of pupus, boy, allied to puer, from root pm- or peu-, to beget, cf. "pupa," Lat. for " doll," the name given to the stage intervening between the larval and imaginal stages in certain insects)
pupil, Heinrich See also:Hertz, and the latter finally gave an experimental demonstration of electromagnetic waves, the " Hertzian waves," on which wireless telegraphy depends, and the velocity of which is the same as that of light. The last investigations of Helmholtz related to problems in theoretical mechanics, more especially as to the relations of See also:matter to the ether, and as to the See also:distribution of energy in See also:mechanical systems. In particular he explained the principle of least action, first advanced by P. L. M. de See also:Maupertuis, and developed by See also:Sir W. R. See also:- HAMILTON
- HAMILTON (GRAND or ASHUANIPI)
- HAMILTON, ALEXANDER (1757-1804)
- HAMILTON, ANTHONY, or ANTOINE (1646-1720)
- HAMILTON, ELIZABETH (1758–1816)
- HAMILTON, EMMA, LADY (c. 1765-1815)
- HAMILTON, JAMES (1769-1831)
- HAMILTON, JAMES HAMILTON, 1ST DUKE OF (1606-1649)
- HAMILTON, JOHN (c. 1511–1571)
- HAMILTON, MARQUESSES AND DUKES OF
- HAMILTON, PATRICK (1504-1528)
- HAMILTON, ROBERT (1743-1829)
- HAMILTON, SIR WILLIAM
- HAMILTON, SIR WILLIAM (1730-1803)
- HAMILTON, SIR WILLIAM ROWAN (1805-1865)
- HAMILTON, THOMAS (1789-1842)
- HAMILTON, WILLIAM (1704-1754)
- HAMILTON, WILLIAM GERARD (1729-1796)
Hamilton, of quaternion fame. Helmholtz also wrote on philosophical and aesthetic problems. His position was that of an empiricist, denying the See also:doctrine of innate ideas and holding that all knowledge is founded on experience, hereditarily transmitted or acquired.
The life of Helmholtz was uneventful in the usual sense. He was twice married, first, in 1849, to See also:Olga von Velten (by whom he had two See also:children, a son and daughter), and secondly, in 1861, to See also:Anna von See also:Mohl, of a Wurtemberg See also:family of high social position. Two children were born of this See also:marriage, a son, See also:Robert, who died in 1889, after showing in experimental physics indications of his father's See also:genius, and a daughter, who married a son of See also:Werner von See also:Siemens. Helmholtz was a man of See also:simple but refined tastes, of See also:noble See also:carriage and somewhat austere manner. His life from first to last was one of devotion to science, and he must be accounted, on intellectual grounds, one of the foremost men of the 19th century.
See L. Konigsberger, Hermann von Helmholtz (1902; See also:English See also:translation by F. A. Welby, See also:- OXFORD
- OXFORD, EARLS OF
- OXFORD, EDWARD DE VERE, 17TH EARL
- OXFORD, JOHN DE VERE, 13TH EARL OF (1443-1513)
- OXFORD, PROVISIONS OF
- OXFORD, ROBERT DE VERE, 9TH EARL OF (1362-1392)
- OXFORD, ROBERT HARLEY, 1ST
Oxford, 1906); J. G. M°Kendrick, H. L. F. von Helmholtz (1899). (J. G.
End of Article: HELMHOLTZ, HERMANN LUDWIG FERDINAND VON (1821-1894)
Additional information and Comments
There are no comments yet for this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.
Links to articles and home page are always encouraged.
|
del.icio.us it!