See also:

• HERMANN, JOHANN GOTTFRIED JAKOB (1772–1848)
• HERMANN, KARL FRIEDRICH (1804–1855)

HERMANN See also:

• LUDWIG, KARL FRIEDRICH WILHELM (1816—1895)
• LUDWIG, OTTO (1813-1865)

LUDWIG See also:

• FERDINAND
• FERDINAND (1577-1650)
• FERDINAND (COLOGNE)
• FERDINAND (Span. Fernando or Hernando; Ital. Ferdinando or Ferrante; in O. H. Ger. Herinand, i.e. " brave in the host," from O. H. G. Heri, "army," A. S. here, Mod. Ger. Heer, and the Goth. nan]jan, " to dare ")
• FERDINAND, MAXIMILIAN KARL LEOPOLD MARIA

FERDINAND VON See also:

• HERMANN LUDWIG FERDINAND VON HELMHOLTZ (1821-1894)

HELMHOLTZ (1821-1894)  , See also:

• GERMAN
• GERMAN, DUTCH AND SCANDINAVIAN

German philosopher and See also:

• MAN
• MAN, ISLE OF (anc. Mona)

man of. See also:

• SCIENCE (Lat. scientia, from scire; to learn, know)

science, was See also:

• BORN, IGNAZ, EDLER VON (1742–1791)

born on the 31st of See also:

• AUGUST (originally Sextilis)

August 1821 at See also:

• POTSDAM

Potsdam, near See also:

• BERLIN
• BERLIN, CONGRESS AND TREATY OF
• BERLIN, ISAIAH (1725–1799)

Berlin . His See also:

• FATHER

father, See also:

• FERDINAND
• FERDINAND (1577-1650)
• FERDINAND (COLOGNE)
• FERDINAND (Span. Fernando or Hernando; Ital. Ferdinando or Ferrante; in O. H. Ger. Herinand, i.e. " brave in the host," from O. H. G. Heri, "army," A. S. here, Mod. Ger. Heer, and the Goth. nan]jan, " to dare ")
• FERDINAND, MAXIMILIAN KARL LEOPOLD MARIA

Ferdinand, was a teacher of See also:

• PHILOLOGY

philology and See also:

• PHILOSOPHY (Gr. gthos, fond of, and vo4 (a, wisdom)

philosophy in the gymnasium, while his See also:

• MOTHER

mother was a Hanoverian See also:

• LADY (0. Eng. hlaefdige, Mid. Eng. ldfdi, lavedi; the first part of the word is hldf, loaf, bread, as in the corresponding hldford, lord; the second part is usually taken to be from the root dig-, to knead, seen also in " dough "; the sense development fr

lady, a lineal descendant of the See also:

• GREAT

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, WILLIAM (1621–1670)
• PENN, WILLIAM (1644-1718)

Penn . Delicate in See also:

• EARLY
• EARLY, JUBAL ANDERSON (1816-1894)

early See also:

• LIFE

life, See also:

• HELMHOLTZ, HERMANN LUDWIG FERDINAND VON (1821-1894)

Helmholtz became by See also:

• HABIT (through the French from Lat. habitus, from habere, to have, hold, or, in a reflective sense, to be in a certain condition; in many of the English senses the French use habitude, not habit)

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, HIRAM (1805-1873)

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 (from Lat. ad-tendo, await, expect; the condition of being " stretched " or " tense ")

attention was directed to the higher See also:

• MATHEMATICS (Gr. /saBnµar1Kil, Sc. vOcvn or E7rlQTt'µn; from p iN.La, "learning" or "science ")

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
• ARMY (from Fr. armee, Lat. armata)

army . In 1842 he wrote a thesis in which he announced the See also:

• DISCOVERY

discovery of See also:

• NERVE (Lat. nervus, Gr. vevpov, a bowstring)

nerve-cells in ganglia . This was his first See also:

• WORK

work, and from 1842 to 1894, the See also:

• YEAR

year of his See also:

• DEATH

death, scarcely a year passed without several important, and in some cases See also:

• EPOCH (Gr. E7roxij, holding in suspense, a pause, from E1rxav, to hold up, to stop)

epoch-making, papers on scientific subjects coming from his See also:

• PEN (Lat. penna, a feather, pen)

pen . He lived in Berlin from 1842 to 1849, when he became See also:

• PROFESSOR (the Latin noun formed from the verb profiteri, to declare publicly, to acknowledge, profess)

professor of See also:

• PHYSIOLOGY (from Gr. 4 i s, nature, and koyos, discourse)

physiology in See also:

• KONIGSBERG (Polish Krolewiec)

Konigsberg . There he remained from 1849 to 1855, when he removed to the See also:

• CHAIR (in. Mid. Eng. chcere, through O. Fr. chaire or chaiere, from Lat. cathedra, later caledra, Gr. xaOi3pa, seat, cf. "cathedral"; the modern Fr. form chaise, a chair, has been adopted in English with a particular meaning as a form of carriage; chaire

chair of physiology in See also:

• BONN

Bonn . In 1858 he became professor of physiology in See also:

• HEIDELBERG

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

post of director of the physico-technical See also:

• INSTITUTE (from Lat. instituere, to establish or set up)

institute at See also:

• CHARLOTTENBURG

Charlottenburg, near Berlin, and he held the two positions together until his death on the 8th of See also:

• SEPTEMBER (Lat. septem, seven)

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

optics, physiological See also:

• ACOUSTICS (from the Gr. &eobav to hear)

acoustics, See also:

• CHEMISTRY
• CHEMISTRY (formerly "chymistry"; Gr. xvµela; for derivation see ALCHEMY)

chemistry, mathematics, See also:

• ELECTRICITY

electricity and See also:

• MAGNETISM
• MAGNETISM, TERRESTRIAL

magnetism, See also:

• METEOROLOGY (Gr. JerEwpa, and hb'yos, i.e. the science of things in the air)

meteorology and theoretical See also:

• MECHANICS

mechanics .

At an early See also:

• AGE (Fr. age, through late Lat. aetaticum, from aetas)

age he contributed to our knowledge of the causes of putrefaction and See also:

• FERMENTATION

fermentation . In physiological science he investigated quantitatively the phenomena of See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

animal See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat, and he was one of the earliest in the field of animal electricity . He studied the nature of See also:

• MUSCULAR

muscular contraction, causing a muscle to See also:

• RECORD (Lat. recordari, to recall to mind, from cor, heart or mind)

record its movements on a smoked See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

glass See also:

• PLATE

plate, and he worked out the problem of the velocity of the See also:

• NERVOUS

nervous impulse both in the motor nerves of the See also:

• FROG

frog and in the sensory nerves of man . In 1847 Helmholtz read to the See also:

• PHYSICAL

Physical Society of Berlin a famous See also:

• PAPER
• PAPER (Fr. papier, from Lat. papyrus)

paper, Uber See also:

• DIE
• DIE (Fr. de, from Lat. datum, given)

die Erhaltung der Kraft (on the conservation of force), which became one of the epoch-making papers of the See also:

• CENTURY (from Lat. centuria, a division of a hundred men)

century; indeed, along with J . R . See also:

• MAYER, JOHANN TOBIAS (1723-1762)
• MAYER, JULIUS ROBERT (1814-1878)

Mayer, J . P . See also:

• JOULE, JAMES PRESCOTT (1818–1889)

Joule and W . See also:

• THOMSON, JAMES (1822-1892)
• THOMSON, JAMES (1834-1882)
• THOMSON, JAMES (r700-1748)
• THOMSON, JOHN (1778-184o)
• THOMSON, JOSEPH (1858-1895)
• THOMSON, SIR CHARLES WYVILLE (1830-1882)
• THOMSON, THOMAS (1773-1852)
• THOMSON, WILLIAM (1819-189o)

Thomson (See also:

• LORD
• LORD (O. Eng. hldford, i.e. hldfweard, the warder or keeper of bread, hlIf, loaf; the word is not represented in any other Teutonic language)
• LORD, JOHN (1810-1894)

Lord See also:

• KELVIN, WILLIAM THOMSON, BARON (1824-1907)

Kelvin), he may be regarded as one of the founders of the now universally received See also:

• LAW
• LAW (0. Eng. lagu, M. Eng. lawe; from an old Teutonic root lag, " lie," what lies fixed or evenly; cf. Lat. lex, Fr. loi)
• LAW, JOHN (1671—1729)
• LAW, WILLIAM (1686-1761)

law of the conservation of See also:

• ENERGY (from the Gr. ivipyela; iv, in, ipyov, work)

energy . The year 1851, while he was lecturing on physiology at Konigsberg, saw the brilliant invention of the ophthalmoscope, an See also:

• INSTRUMENT (Lat. instrumentum, from insincere, to build up, furnish, arrange, prepare)

instrument which has been of in-estimable value to See also:

• MEDICINE

medicine . It arose from an See also:

• ATTEMPT (Lat. adtemptare, attentare, to try)

attempt to demonstrate to his class the nature of the glow of reflected See also:

• LIGHT

light sometimes seen in the eyes of animals such as the See also:

• CAT
• CAT, CIVET
• CAT, HOUSE

cat . When the great ophthalmologist, A. von See also:

• GRAFE, ALBRECHT VON (1828–187o)
• GRAFE, HEINRICH (1802–1868)
• GRAFE, KARL FERDINAND VON (1787–1840)

Grafe, first saw the fundus of the living human See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye, with its optic disc and See also:

• BLOOD

blood-vessels, his See also:

• FACE (from Lat. fades, derived either from facere, to make, or from a root fa-, meaning " appear "; cf. Gr. cbatvstv)

face flushed with excitement, and he cried, " Helmholtz has unfolded to us a new See also:

• WORLD

world!" Helmholtz's contributions to physiological optics are of great importance .

He investigated the See also:

• OPTICAL

optical constants of the eye, measured by his invention, the ophthalmometer, the radii of curvature of the crystalline See also:

• LENS
• LENS (from Lat. lens, lentil, on account of the similarity of the form of a lens to that of a lentil seed)

lens for near and far See also:

• VISION (from Lat. videre, to see), or SIGHT

vision, explained the mechanism of See also:

• ACCOMMODATION (Lat. accommodare, to make fit, from ad, to, cum, with, and modus, measure)

accommodation by which the eye can See also:

• FOCUS (Latin for " hearth " or " fireplace ")

focus within certain limits, discussed the phenomena of See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour vision, and gave a luminous See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

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
• YOUNG, A
• YOUNG, ARTHUR (1741-1820)
• YOUNG, BRIGHAM (1801-1877)
• YOUNG, CHARLES MAYNE (1777–1856)
• YOUNG, EDWARD (1683–1765)
• YOUNG, JAMES (1811-1883)
• YOUNG, THOMAS (1773-1829)

Young, showing the three See also:

• PRIMARY

primary See also:

• COLOURS, MILITARY

colours to be red, See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green and See also:

• VIOLET

violet, and he applied the theory to the explanation of colour-See also:

• BLINDNESS

blindness . His great work on Physiological Optics (1856—1866) is by far the most important See also:

• BOOK

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 (common Teut.; O.E. are, Ger. Ohr, Du. oor, akin to Lat. auris, Gr. ovs)

ear, and he discussed the physiological See also:

• ACTION

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 (from Lat. percipere, to perceive)

perception of quality of See also:

• TONE, THEOBALD WOLFE (1763-1798)

tone . He showed, both by See also:

• ANALYSIS (Gr. avci and Meta, to break up into parts)

analysis and by See also:

• SYNTHESIS (Gr. a6vOeacs, from avvrcBivac, to put together)

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

developed the theory of See also:

• DIFFERENTIAL

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
• PITCH, MUSICAL

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 (Lat. forma)

form of the cavity while singing it, and this independently of the pitch of the See also:

• NOTE
• NOTE (Lat. nota, mark, sign, from noscere, to know)

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
• DYNAMICS (from Gr. bbvayts, strength)

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, JAMES THOMAS (1817-1881)

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
• ELECTRICAL (or ELECTROSTATIC) MACHINE

electrical oscillations from 186o to 1871 ,and in the latter year he announced that the velocity of the See also:

• PROPAGATION

propagation of electromagnetic See also:

• INDUCTION (from Lat. inducere, to lead into; cf. Gr. ilrayu yli)

induction was about 314,000 metres per second . See also:

• FARADAY, MICHAEL (1791-1867)

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

dielectric substances . This led Clerk See also:

• MAXWELL
• MAXWELL, JAMES CLERK (1831–1879)

Maxwell to See also:

• FRAME

frame his theory of electro-dynamics, in which electrical impulses were assumed to be transmitted through the See also:

• ETHER, (C2H5)2O

ether by waves . G . F . See also:

• FITZGERALD
• FITZGERALD, EDWARD (1809–1883)
• FITZGERALD, LORD E
• FITZGERALD, LORD EDWARD (1763-1798)
• FITZGERALD, LORD THOMAS (loth earl of Kildare), (1513-1537)
• FITZGERALD, RAYMOND, or REDMOND (d. ca. 1182)

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, HEINRICH RUDOLF (1857-1894)
• HERTZ, HENRIK (1797–1870)

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

matter to the ether, and as to the See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution of energy in See also:

• MECHANICAL

mechanical systems . In particular he explained the principle of least action, first advanced by P . L . M. de See also:

• MAUPERTUIS, PIERRE LOUIS MOREAU DE (1698–1759)

Maupertuis, and developed by See also:

• SIR

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

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

Olga von Velten (by whom he had two See also:

• CHILDREN, LAW RELATING TO

children, a son and daughter), and secondly, in 1861, to See also:

• ANNA
• ANNA (Hindustani ana)
• ANNA, BALDASARRE

Anna von See also:

• MOHL, HUGO VON (1805–1872)
• MOHL, JULIUS VON (1800–1876)

Mohl, of a Wurtemberg See also:

• FAMILY

family of high social position . Two children were born of this See also:

• MARRIAGE

marriage, a son, See also:

• ROBERT
• ROBERT (1275—1343)
• ROBERT, HUBERT (1753-1808)
• ROBERT, LOUIS LEOPOLD (1794-1835)

Robert, who died in 1889, after showing in experimental physics indications of his father's See also:

• GENIUS (from Lat. genere, gignere)

genius, and a daughter, who married a son of See also:

• WERNER, ABRAHAM GOTTLOB (1750-1817)
• WERNER, ANTON ALEXANDER VON (1843– )
• WERNER, FRIEDRICH LUDWIG ZACHARIAS (1768–1823)

Werner von See also:

• SIEMENS, ERNST WERNER VON (1816-1892)
• SIEMENS, SIR WILLIAM [KARL WILHELM] (1823-1883)

Siemens . Helmholtz was a man of See also:

• SIMPLE

simple but refined tastes, of See also:

• NOBLE, SIR ANDREW (1832- )

noble See also:

• CARRIAGE

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, See also:

• HERMANN, JOHANN GOTTFRIED JAKOB (1772–1848)
• HERMANN, KARL FRIEDRICH (1804–1855)

Hermann von Helmholtz (1902; See also:

• ENGLISH

English See also:

• TRANSLATION

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 .