See also:

• SUN
• SUN (0. Eng. sonne, Ger. sonne. Fr. soleil, Lat. sol, Gr. ijXior, from which comes helio- in various English compounds)

SUN (0. Eng. sonne, Ger. sonne. Fr. soleil, See also:

• LAT

Lat. sol, Gr. ijXior, from which comes helio- in various See also:

• ENGLISH

English compounds)  , the name of the central See also:

• BODY

body of the See also:

• SOLAR, SOLLER (Lat. solarium, Fr.• galetas, Ital. solaio)

solar See also:

• SYSTEM

system, the luminous See also:

• ORB

orb from which the See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth receives See also:

• LIGHT

light and 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; (see See also:

• SUNSHINE

SUNSHINE); hence by See also:

• ANALOGY (Gr. avaXo-yLa, proportion)

analogy other heavenly bodies which See also:

• FORM (Lat. forma)

form the centre of systems are called suns . To understand the phenomena of the See also:

• SUN
• SUN (0. Eng. sonne, Ger. sonne. Fr. soleil, Lat. sol, Gr. ijXior, from which comes helio- in various English compounds)

sun, we should reproduce them upon the earth; but this is clearly impossible since they take See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place at temperatures which volatilize all known substances . Hence our only guides are such See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general See also:

• LAWS

laws of See also:

• MECHANICS

mechanics and physics as we can hardly believe any circumstances will falsify . But it must be remembered that these require extrapolation from experience sometimes sufficiently remote, and it is possible they may See also:

• LEAD
• LEAD (pronounced iced)

lead to statements that are obscure, if not contradictory . The body of the sun must consist of uncombined gases; at the See also:

• SURFACE

surface the temperature is some 2000° C. above the boiling point of See also:

• CARBON (symbol C, atomic weight 12)

carbon, and a little way within the body it may probably exceed the See also:

• CRITICAL (in alphabetical order of authors)

critical point at which increase of pressure can produce the liquid See also:

• STATE
• STATE, GREAT OFFICERS OF

state in any substance . But as the mean densityexceeds that of See also:

• WATER

water, and probably falls but little from the centre to the surface, these gases are gases only in the sense that if the pressure of neighbouring and outward parts gravitating to-wards the centre were relaxed, they would expand explosively, as we see happening in the eruptive prominences . They have lost completely the' gaseous characteristic of producing a See also:

• LINE

line spectrum, and radiate like incandescent solids . The surface region which yields a continuous spectrum is called the photo-See also:

• SPHERE (Gr. vclsa?pa, a ball or globe)

sphere; it possesses optically a See also:

• SHARP, GRANVILLE (1735-1813)
• SHARP, JAMES (1618-1679)
• SHARP, JOHN (1645-1714)
• SHARP, RICHARD (1759-1835)
• SHARP, WILLIAM (1749-1824)
• SHARP, WILLIAM (1856-1905)

sharp boundary, which is generally a perfect sphere, but shows occasionally at the rim slight depressions or more rarely elevations . Enclosing the photo-sphere is a truly gaseous envelope which is called the See also:

• CHROMOSPHERE (from Gr. xpwµa, colour, and vqSaipa, a sphere)

chromosphere, and which shows a spectrum of See also:

• BRIGHT, JOHN (1811-188g)
• BRIGHT, SIR CHARLES TILSTON

bright lines when we can isolate its emission from that of the photosphere . This envelope is also sharply defined, but its normal See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance is compared to the serrations which See also:

• BLADES, WILLIAM (1824-1890)

blades of grass show on the skyline of a See also:

• HILL
• HILL (0. Eng. hyll; cf. Low Ger. hull, Mid. Dutch hul, allied to Lat. celsus, high, collis, hill, &c.)
• HILL, A
• HILL, AARON (1685-175o)
• HILL, AMBROSE POWELL
• HILL, DANIEL HARVEY (1821-1889)
• HILL, DAVID BENNETT (1843–1910)
• HILL, GEORGE BIRKBECK NORMAN (1835-1903)
• HILL, JAMES J
• HILL, JOHN (c. 1716-1775)
• HILL, MATTHEW DAVENPORT (1792-1872)
• HILL, OCTAVIA (1838– )
• HILL, ROWLAND (1744–1833)
• HILL, SIR ROWLAND (1795-1879)

hill, and it is disturbed by the outbursts, called prominences, of which details are given below . Outside this again is an envelope of See also:

• MATTER

matter of enormous extent and extreme tenuity, whether gaseous or partly See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute liquid or solid drops, which is called the See also:

• CORONA (Lat. for " crown ")

corona . It has no sharp boundary, its brightness diminishes rapidly as we recede from the See also:

• LIMB

limb, and such structure as it .shows consists of See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long streaks or filaments extending outwards from the limb in broad curved sweeps .

Finally there is the envelope of still vaster extent and of unknown constitution which gives the zodiacal light (q.v.); its greatest extent is along the See also:

• ECLIPTIC

ecliptic, but it can also be certainly traced for 35° in a perpendicular direction . The See also:

• LOWER

lower gaseous cloaks absorb a large See also:

• PART

part of the light admitted by the photosphere, and especially at the limb and for the more refrangible rays the loss of intensity is very marked . In the instants when a sharp See also:

• IMAGE (Lat. imago, perhaps from the same root as imitari, copy, imitate)

image of the photosphere is seen or photographed, it shows a granulated appearance like See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white flakes strewed fairly evenly upon a dark .ground . The See also:

• FIGS

figs . I, 2, 3, 4 (See also:

• PLATE

plate) show enlargements from photo- General graphs by Hansky at Pulkowa (See also:

• JUNE

June 25, 1905); Appearance they are separated by intervals from 25 to 8o ofPhotoseconds, and he has succeeded in showing identity sphere . in many of the granules, or more properly, clouds represented . Thus they exhibit at once general appearance and its changes . The diameters range from 400 M. or less up to 1200 m., and the speeds relative to the spot range up to 2 or 3 M. per second . M . Hansky believes these motions may be the consequences of matter rising from below and thrusting the surface See also:

• GROUPS
• GROUPS, THEORY

groups aside . Usually the changes are such that it is impossible even to recognize the formations in successive photographs . Besides granulations the sun's disk shows, as a See also:

• RULE

rule, one or more spots or groups of spots .

Each spot shows with more or less completeness a See also:

• RING (O.E. hring; a word common to Teutonic languages; and probably cognate with the Lat. circus, Gr. KtpKOS or KpLKOS, Skt'. chakra, wheel, circle, cf. also " harangue "); in art, a band of circular shape of varying sizes, made of any material and used f

ring-shaped See also:

• PENUMBRA (Lat. paene, almost, umbra, a shadow)

penumbra enclosing a darker See also:

• UMBRA (Lat. for shade or shadow)

umbra; the umbra, which looks See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black beside the photosphere, is actually about as brilliant as limelight . In the neighbourhood surrounding the penumbra the granules appear to be packed more closely, forming brilliant patches called faculae . In the shape of a spot there is neither rule nor permanence, though those that are nearly circular seem to resist See also:

• CHANGE (derived through the Fr. from the Late Lat. cambium, cambiare, to barter; the ultimate derivation is probably from the root which appears in the Gr. «a urmu', to bend)

change better than the others . They arise from combinations of smaller spots, or from nothing, in a See also:

• SHORT, FRANCIS JOB (1857– )

short See also:

• PERIOD
• PERIOD (Gr. irepioSos, a going or way round, circuit, aepi, round, and &Sis, way, road)

period, say a See also:

• DAY (O. Eng. dreg, Ger. Tag; according to the New English Dictionary, " in no way related to the Lat. dies")
• DAY, JOHN (1574-1640?)
• DAY, THOMAS (1748-1789)

day . They are never wholly quiescent . See also:

• BRIDGES
• BRIDGES, ROBERT (1844– )

Bridges, more brilliant than the See also:

• REST (O. Eng. rest, reste, bed, cognate with other Teutonic forms, e.g. Ger. Rast, Riiste, rest, and probably Gothic Rasta, league, i.e. resting or stopping place)

rest of the photosphere, form across them, and they may See also:

• DIVIDE

divide into two parts which See also:

• SEPARATE

separate from one another with See also:

• GREAT

great velocity . The largest spots are easily seen by the naked 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, if the brilliancy of the disk is veiled; the umbra may be many—ten or more—diameters of the earth in breadth . The length of their See also:

• LIFE

life is difficult to assign, because there is some tendency for a new See also:

• GROUP

group to arise where an old one has disappeared; but one is recorded which appeared in the same place for eighteen months; the See also:

• AVERAGE

average is perhaps two months . They are carried across the disk by the sun's rotation, partaking in the See also:

• EQUATORIAL

equatorial See also:

• ACCELERATION (from Lat. accelerare, to hasten, celer, quick)

acceleration; they also show marked displacements of their own, whether with, or relative to, the neighbouring photosphere does not appear; at the beginning of their life they usually outrun the average daily rotation appropriate to their See also:

• LATITUDE (Lat. latitudo, latus, broad)

latitude . Spots are rarely found on the See also:

• EQUATOR (Late Lat. aequator, from aequare, to make equal)

equator, or consider first a frictionless fluid . The equations of surfaces of equal angular See also:

• MOTION (Lat. motio, from movere, to move)
• MOTION, LAWS OF

motion would be of the form r=R (1—e See also:

• COS
• COS, or STANKO (Ital. Stanchio, Turk. Islan-keui, by corruption from Etc rav KW)

cos'e), where is proportional to the square of the angular motion, supposed small, and R increases as e diminishes . Consider the traces these surfaces cut on any sphere r =a: we have de/de = 2e sine cos O/(cost e — aR-'dR/de}, which is See also:

• POSITIVE (or PORTABLE) ORGAN

positive and has a maximum in the See also:

• MIDDLE

middle latitudes; so that, proceeding from the See also:

• POLE (FAMILY)
• POLE, REGINALD (1500-1558)
• POLE, RICHARD DE LA (d. 1525)
• POLE, WILLIAM (1814—1900)

pole to the equator along any See also:

• MERIDIAN
• MERIDIAN (from the Lat. meridianus, pertaining to the south or mid-day)

meridian, the angular velocity would continually in-crease, at a See also:

• RATE

rate which was greatest in the middle latitudes .

This is exactly what the observations show . Now if this state be supposed established in a frictionless fluid, the See also:

• CONSIDERATION (from Lat. considerare, to look at closely, examine, generally taken to be from con-, and the base seen in sidus, sideris, a star, the word being supposed to be originally an astrological or astronomical term)

consideration of See also:

• INTERNAL

internal See also:

• FRICTION (from Lat. fricare, to rub)

friction would simply extend the characteristics found at any spot to the neighbourhood,. and there-fore if the boundary were a sphere and so for a frictionless fluid an exception, it would tease to be an exception when we allow for viscosity . But this theory gives no See also:

• CLUE

clue to the results See also:

• RELATING

relating to See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen, which belongs to a high level, and which See also:

• ADAMS
• ADAMS, ANDREW LEITH (1827-1882)
• ADAMS, CHARLES FRANCIS (1807-1886)
• ADAMS, HENRY (1838— )
• ADAMS, HENRY CARTER (1852— )
• ADAMS, HERBERT (i858— )
• ADAMS, HERBERT BAXTER (1850—1901)
• ADAMS, JOHN (1735–1826)
• ADAMS, JOHN QUINCY (1767-1848)
• ADAMS, SAMUEL (1722-1803)
• ADAMS, THOMAS (d. c. 1655)
• ADAMS, WILLIAM (d. 162o)

Adams has shown to move with an angular velocity decidedly greater than the equatorial angular velocity below it, and not to show any sign of falling off towards the poles . It is useful to form a conception of the See also:

• MECHANICAL

mechanical state within the sun's body . Its temperature must be dominated directly or indirectly by the surface See also:

• RADIATION, THEORY OF

radiation, and since the mechanical matter is gaseous and so open to redistribution, the state same is true of See also:

• DENSITY (Lat. densus, thick)

density and pressure . It is true that Thternat/yi within the body radiations must be stifled within a short distance of their source; none the less, they will determine a temperature gradient, falling from the centre to the See also:

• BORDERS, THE

borders, though for the most part falling very slowly, and we may ask what relative temperatures in different parts would maintain themselves if once established . Stefan's 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 radiation ac-cording to the See also:

• FOURTH

fourth See also:

• POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power of the temperature is too difficult to pursue, but if we are content with cognate results we can follow them out mathematically in a hypothetical law of the first power . We then find that the density would increase as we go outwards, at first slowly, but finally with extreme rapidity, the last tenth of the See also:

• RADIUS

radius comprising See also:

• HALF

half the See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass . The radiation from such a body would be practically nil, no matter how hot the centre was . Of course such a state would be statically unstable . It would never get established because currents would arise to See also:

• EXCHANGE

exchange the positions of the hotter, less dense, inner parts and the cooler, more dense, See also:

• OUTER

outer ones . By this interchange the inner parts would be opened out and the See also:

• TOTAL

total radiation raised .

Since the only cause for these convection currents is the statical instability produced by radiation, and the rapid stifling of radiations within the body produces there a temperature gradient falling very slowly, they would be for the most part extremely slight . Only near the surface would they become violent, and only there would there be a rapid fall of temperature and density . Through the See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main body these would remain nearly See also:

• CONSTANT, BENJAMIN (1845-1902)

constant . Indeed it seems that, in the final See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution of density throughout the part which is not subject to violent convection currents, it must increase slightly from the centre outwards, since the currents would cease altogether as soon as a See also:

• UNIFORM

uniform state was restored . In the outer strata a different state must prevail . Rapidly falling temperature must (and visibly does) produce furious motions which wholly outrun See also:

• MERE
• MERE, ADALBERT (1838-1909)

mere restoration of statical See also:

• BALANCE (derived through the Fr. from the Late Lat. bilantia, an apparatus for weighing, from bi, two, and lanx, a dish or scale)

balance . Portions change places airs rapidly and so continually, that we may take it, where any average is reached, the See also:

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

energy is so distributed that there is neither gain nor loss when such a change occurs . This is the law of convective See also:

• EQUILIBRIUM (from the Lat. aequus, equal, and libra, a balance)

equilibrium: But in the sun's See also:

• ATMOSPHERE (Gr. fir µ6r, vapour; orkaipa, a sphere)

atmosphere See also:

• GRAVITATION (from Lat. gravis, heavy)

gravitation alone is a misleading See also:

• GUIDE (in Mid. Eng. gyde, from the Fr. guide; the earlier French form was guie, English " guy," the d was due to the Italian form guida; the ultimate origin is probably Teutonic, the word being connected with the base seen in O. Eng. witan, to know)

guide . Convective equilibrium, which depends upon it, gives far too steep a temperature gradient, for it yields a temperature of 6000° only aoo m. within the See also:

• FREE

free surface, whereas the chromosphere is of an average thickness- of 5000 In., and attains that temperature only at its such were the See also:

• CASE
• CASE, JOHN (d. 1600)

case the observed phenomenon would arise . For , See also:

• BASE

base . Probably the See also:

• FACTOR (from Lat. facere, to make or do)

factor which thus diminishes the effective more than .3,5° N. or S. of it, and at . 45° are practically unknown .

Their occurrence within these zones follows statistically a uniform law (see See also:

• AURORA
• AURORA (perhaps through a form ausosa from Sansk. ush, to burn ; the common idea of " brightness " suggests a connexion with aurum, gold)

AURORA) . Other See also:

• INFORMATION (from Lat. informare, to give shape or form to, to represent, describe)

information about the spots is given below, in connexion with their spectra . It may be said that nothing definite has.. been established as to what they are . The statement known as A . See also:

• WILSON, ALEXANDER (1766-1813)
• WILSON, HENRY (1812–1875)
• WILSON, HORACE HAYMAN (1786–1860)
• WILSON, JAMES (1742—1798)
• WILSON, JAMES (1835— )
• WILSON, JAMES HARRISON (1837– )
• WILSON, JOHN (1627-1696)
• WILSON, JOHN (178 1854)
• WILSON, ROBERT (d. 1600)
• WILSON, SIR DANIEL (1816–1892)
• WILSON, SIR ROBERT THOMAS (1777—1849)
• WILSON, SIR WILLIAM JAMES ERASMUS
• WILSON, THOMAS (1663-1755)
• WILSON, THOMAS (c. 1525-1581)
• WILSON, WOODROW (1856— )

Wilson's theory (1774), that they, are hollows n, the photosphere, long supposed to be proved by See also:

• PERSPECTIVE (Lat. peespicere, to see through)

perspective effects as the spot approached the limb, is discredited by F . Howlett's careful drawings, which, however, do not establish the contrary . To draw a trustworthy conclusion it is necessary that the ;spot should be quiescent, show a well-See also:

• DEVELOPED

developed and fairly symmetrical penumbra, and be observed near the limb and also near the centre, and these conditions are satisfied in so few cases as to withdraw all statistical force from the conclusion . Figs . 5, 6, . 7, 8 (plate) are reproductions of the See also:

• GREENWICH

Greenwich photographs of the sun from the 30th of See also:

• JANUARY

January to the . 8th of See also:

• FEBRUARY

February 1905 . The first, taken alone, might seem to See also:

• BEAR
• BEAR, BLACK
• BEAR, BROWN
• BEAR, GRIZZLY
• BEAR, ISABELLINE
• BEAR, WHITE

bear out Wilson's theory, but the others show that the penumbra is really very unsymmetrical and much broader on . the See also:

• SIDE
• SIDE (mod. Eski Adalia)

side towards the limb, apart from anything which . perspective may have to say .

The photosphere does not rotate in one piece, lower latitudes outrunning higher . This was discovered by R . C .. See also:

• CARRINGTON, CHARLES

Carrington from observations of the spots, extending' from 1853 Rotation of to 1861, from which he determined also the position the Photo- of the sun's See also:

• AXIS (Lat. for " axle ")

axis . But conclusions from the spots sphere- are full of anomalies . E . W . Maunder and Mrs Maunder found that different spots in the same See also:

• ZONE (Gr. 'WV77, a girdle, from 'wvvLvay to gird)

zone differ more than do the means for different zones, while a long-lived spot settles down to give more consistent results than are furnished by spots of one apparition . In the span of two See also:

• COMPLETE

complete sun-spot periods no See also:

• EVIDENCE (Lat. evidentia, evideri, to appear clearly)

evidence was found of periodic or other change with See also:

• LAPSE (Lat. lapses, a slip or departure)

lapse of 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 . The problem still awaits complete discussion . The irregularities incidental to use of the spots are escaped by comparing the relative Doppler displacements of the same spectral line as given by the receding,and advancing limbs of the sun . The observation is a delicate one, and was first success-fully handled by N .

C . Dunk in 189o . But his determinations, repeated recently (See also:

• ARTA (Narda, i.e. iv "Ap&a, or Zarta, i,e. eis "Apra)
• ARTA, GULF OF (anc. Sinus Ambracius)

Arta upsal . IV. vol. i., 1907) as well as those of J . See also:

• HALM, CARL FELIX (18o9-1882)

Halm at See also:

• EDINBURGH

Edinburgh (As, . Nach. vol . 173, 1007), are superseded by a photographic treatment of the problem by W . S . Adams (Astrophys . Journ., See also:

• XXVI

xxvi., 1907) . The See also:

• DIAGRAM

diagram (fig . 9) shows Adams's value for the angular velocity f for different latitudes 4, the dots, representing the actual observations .

Fig. to shows the consequent distortion of a set of meridians after one revolution (at See also:

• LAT

lat . 30°) . An important feature added to the discussion by Adams is the different behaviour of spectral lines which are believed to originate, at different levels . The data given above refer to the mean See also:

• REVERSING

reversing layer . Lines of lanthanum. and carbon which are believed to belong to a See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low level showed' systematically smaller angular velocity than the average . This promises to be a fertile 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 for future inquiry . Pending more conclusive evidence from the spectroscope, the See also:

• INTERPRETATION (from Lat. interpretari, to expound, explain, inter pres, an agent, go-between, interpreter; inter, between, and the root pret-, possibly connected with that seen either in Greek 4 p4'ew, to speak, or irpa-rrecv, to do)

interpretation of the See also:

• PECULIAR

peculiar surface rotation of the sun appears to ,be that, the. central parts of the body are rotating ' faster than those outside them; for if E the lines can proceed, and its state at the time of emission; the former is indicative only of the rate of loss of energy from the sun by radiation, and is inwoven with a remark-able group of 'See also:

• PHYSICAL

physical theory and experiment, known as the theory of the black body, or as black radiation . The " black body " is an ideal body with surface so constituted as to reflect no part of any radiations that fall upon it; in the case of such a body See also:

• KIRCHHOFF, GUSTAV ROBERT (1824-1887)
• KIRCHHOFF, JOHANN WILHELM ADOLF (1826-1908)

Kirchhoff and See also:

• BALFOUR, FRANCIS MAITLAND (1851-1882)
• BALFOUR, ROBERT (known also as BALFOREUS) (1550?-1625?)
• BALFOUR, SIR JAMES (of Pittendreich) (d. 1583 Or 1584)
• BALFOUR, SIR JAMES, BART

Balfour See also:

• STEWART, ALEXANDER TURNEY (1803-1876)
• STEWART, BALFOUR (1828-1887)
• STEWART, CHARLES (1778–1869)
• STEWART, DUGALD (1753-1828)
• STEWART, J
• STEWART, JOHN (1749—1822)
• STEWART, JULIUS L
• STEWART, SIR DONALD MARTIN (1824–19o0)
• STEWART, SIR HERBERT (1843—1885)
• STEWART, SIR WILLIAM (c. 1540—c. 1605)
• STEWART, STUART
• STEWART, WILLIAM (c. 1480-c. 1550)

Stewart showed that unless energy were to be lost the rate of emission and absorption must be in fixed ratio for each specific See also:

• WAVE

wave-length . The name has no reference to the appearance of the body to the eye; when emitting energy, its radiations will be of all wave-lengths, and if intense enough will See also:

• APPEAL

appeal to the eye as luminous between about wave-lengths 7600 and 4000 tenth-metres; this intensity is a question of temperature, and as it is exquisitely inappropriate to speak of the bulk of the solar radiations as black, the writer will speak instead of amorphous radiations from an ideal radiator . The ideal radiator is realized within any closed cavity, the walls of which are maintained at a definite temperature . The space within is filled with radiations corresponding to this temperature, and these attain a certain equilibrium which permits the energy of radiation to be spoken of as a whole, as a scalar quantity, without See also:

• EXPRESS (through the French from the past participle of the Lat. exprimere, to press out, by transference used of representing objects in painting or sculpture, or of thoughts, &c. in words)

express reference to the See also:

• PROPAGATION

propagation or interference of the waves of which it is composed . It is then found both by experiment and by thermo- dynamic theory that in these amorphous radiations there is for each temperature a definite distribution of the energy over the spectrum according to a law which may be expressed by O5ifr(OX)da, between the wave-lengths X, T-{-da; and as to the form of the See also:

• FUNCTION

function di, See also:

• PLANCK, GOTTLIEB JAKOB (1751–1833)
• PLANCK, KARL CHRISTIAN (1819-188o)

Planck has shown (Sitzungsber .

See also:

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

Berlin Akad . 544) that an intelligible theory can be given which leads to the form 4(OX)="cil{exp(cs/A8)-11, a form which agrees in a satisfactory way with all the experi- ments . Fig . 11 shows the resulting distribution of energy . The enclosed See also:

• AREA

area for each temperature represents the total emission of energy for that tem- perature, the abscissae are the wave- lengths, and the ordinates the corre- sponding intensities of emission for that wave-length . It will be seen that the maximum ordinates See also:

• LIE, JONAS LAURITZ EDEMIL (1833—1908)
• LIE, MARIUS SOPHUS (1842–1899)

lie upon the See also:

• CURVE (Lat. curvus, bent)

curve a8 = constant dotted in the figure, and so, as the temperature of the ideal body rises, the wave-length of most intense radiation shifts from the infra-red towards the luminous part of the radiation as a whole, it is assumed that it is of the See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character of the radiations from an ideal radiator at an appropriate temperature . The first adequate determination of the character as well as amount of solar radiation was made by S . P . See also:

• LANGLEY, SAMUEL PIERPONT (1834-1906)

Langley in 1893 at See also:

• MOUNT, WILLIAM SIDNEY (1807-1868)

Mount See also:

• WHITNEY, ELI (1765-1825)
• WHITNEY, JOSIAH DWIGHT (1819-1896)
• WHITNEY, WILLIAM COLLINS (1841-1904)
• WHITNEY, WILLIAM DWIGHT (1827-1894)

Whitney in See also:

• CALIFORNIA
• CALIFORNIA, LOWER (Baja California)
• CALIFORNIA, UNIVERSITY OF

California (14,000 ft.), with the bolometer, an exceedingly sensitive See also:

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

instrument which he in- vented, and which enabled him to feel his way The solar thermally over the whole spectrum, noting all the Constant . See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief See also:

• FRAUNHOFER, JOSEPH VON (1787-1826)

Fraunhofer lines and bands, which were shown by sharp serrations, or more prolonged depressions of the curve which gave the emissions, and discovering the lines and bands of the invisible ultra-red portion . The bolograph thus obtained must be cleared of the absorption of the earth's atmosphere, and that of the transmitting apparatus—a spectroscope and siderostat . The first in itself requires an elaborate study .

The first essential is an elevated See also:

• OBSERVATORY

observatory; the next is a long See also:

• SERIES (a Latin word from serere, to join)

series of holographs taken at different times of the See also:

• YEAR

year and of the day, to examine the effect of interposing different thicknesses of See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air .and its variation in transparency (chiefly due to water vapour) . It is found that atmospheric absorption is generally greater in summer than in See also:

• WINTER, JOHN STRANGE
• WINTER, PETER (c. 1755-1825)

winter, a difference of 20% being found between See also:

• MARCH
• MARCH (1) (from Fr. marcher, to walk; the earliest sense in French appears to be " to trample," and the origin has usually been found in the Lat. marcus, hammer; Low Lat. marcare, to hammer; hence to beat the road with the regular tread of a soldier: cf.
• MARCH, AUZIAS (c. "1395-1458)
• MARCH, EARLS OF
• MARCH, FRANCIS ANDREW (1825– )

March and See also:

• AUGUST (originally Sextilis)

August; See also:

• MORNING

morning See also:

• HOURS, CANONICAL

hours show a rapid and often irregular increase of transparency, culminating shortly after See also:

• NOON

noon, after which the diminution is slow and comparatively See also:

• REGULAR

regular . The resulting allowances and conclusion are illustrated in fig . 12,taken from an See also:

• ARTICLE (from Lat. articulus, a joint)

article by Langley in the Astrophysical See also:

• JOURNAL
• JOURNAL (through Fr. from late Lat. diurnalis, daily)

Journal (19o3)y xvii . 2 . The integrated emission of energy is given by the area of the outer smoothed curve (4), and the conclusion from this one holograph is that the " solar constant " is 2.54 calories . The meaning of this statement is that, arguing away the earth's atmosphere, which wastes about one-half what is received, a square centimetre, exposed perpendicularly to the sun's rays, would receive sufficient energy per minute to raise 2.54 grams of water 1 ° C . Langley's general determination of the constant was greater than this—3•o to 3.5 dalories; more recently C . G . See also:

• ABBOT (from the Hebrew ab, a father, through the Syriac abba, Lat. abbas, gen. abbatis, O.E. abbad, fr. late Lat. form abbad-em changed in 13th century under influence of the Lat. form to abbat, used alternatively till the end of the 17th century; Ger. Ab
• ABBOT, EZRA (1819-1884)
• ABBOT, GEORGE (1603-1648)
• ABBOT, ROBERT (1588?–1662?)
• ABBOT, WILLIAM (1798-1843)

Abbot at Mount Wilson, with See also:

• INSTRUMENTS

instruments and methods in which Langley's experience is embodied, has reduced it greatly, having proved that one of Langley's corrections was erroneously applied . The results vary between 1.89 and 2•22, and the variation appears to be solar, not terrestrial . Taking the value' at 2•i the earth is therefore receiving energy at the rate of 1.47 kilowatts per square See also:

• METRE ((terpuc?, sc. rFxvf, from Gr. Or poi', measure)

metre, or 1.70 See also:

• HORSE (a word common to Teutonic languages in such forms as hors, hros, ros; cf. the Ger. ross)

horse-power per square yard .

The corresponding intensity at the sun's surface is 4.62 X 104 as great, or 6.79 X Io4 kilowatts per square metre =7.88Xro4 horse-power per square yard—enough to melt a thickness of I3.3 metres (=39.6 ft.) of See also:

• ICE (a word common to Teutonic languages; cf. Ger. Eis)

ice, or to vaporize 1.81 metres ( =5.92 ft.) of water per minute . If we assume that the bolograph of solar energy is simply a graph of amorphous radiation from an ideal radiator, so that the See also:

• CON

con-Temperature stants of Planck's See also:

• FORMULA
• FORMULA (Lat. diminutive of forma, shape, pattern, &c., especially used of rules of judicial procedure)

formula determined terrestrially apply to it, the See also:

• HYPERBOLA

hyperbola of maximum intensity is A8= of the Sun . 2.921 X I07; and as the sun's maximum intensity occurs for about a = 4900, we find the See also:

• ABSOLUTE (Lat. absolvere, to loose, set free)

absolute temperature to be 5960° abs . If we calculate from the total energy emitted, and not from the position of maximum intensity, the same result is obtained within a few degrees . But to See also:

• CALL (from Anglo-Saxon ceallian, a common Teutonic word, cf. Dutch kallen, to talk or chatter)

call this the temperature of the sun's surface is a See also:

• CONVENTION (Lat. conventio, an assembly or agreement, from convenire, to come together)
• CONVENTION, THE NATIONAL

convention, which sets aside some material factors . We may ask first whether the matter of which the surface is composed is such as to give an ideal radiator; it is impossible to See also:

• ANSWER (derived from and, against, and the same root as swear)

answer this, but even if we admit a departure as great as the greatest known terrestrial exception, the estimated temperature is diminished only some 10% . A second gliestion relates to the boundaries . The theory 'refers to radiation homogeneous at all points within a single closed boundary maintained at uniform temperature; in the actual case we have a See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double boundary, one the sun's surface, and the other infinitely remote, or say, non-existent, and at zero temperature; and it is assumed that the density of radiation in the free space varies inversely as the squares of the distance from the sun . Though there is no experiment behind this See also:

• ASSUMPTION, FEAST OF

assumption it can hardly lead to See also:

• ERROR (Lat. error, from errare, to wander, to err)

error . A third question is mote difficult . The temperature gradient at the confines of the photosphere must certainly ascend sharply at first . When we say the sun's temperature is 6000°, of what level are we speaking ?

The fact is that radiation is not a superficial phenomenon but a molar one, and Stefan's law, exact though it be, is not an ultimate theory but only a convenient halting-place, and the radiations of two bodies can only be compared by it when their surfaces are similar in a specific way . One characteristic of such surfaces is fixity, which has no trace of parallel in the sun . The confines of the sun are visibly in a state of turmoil, for which a sufficient cause can be assigned in the relative readiness with which the outer portions part with heat to space, and so condensing produce a state of static instability, so that the outer surface of the sun in place of being fixed is continually circulating, portions at high temperatures rising rapidly from the depths to positions where they will part rapidly with their heat, and then, whether perceived or not, descending again . It is clear that at least a considerable part of the solar radiations comes from a more or less diffuse atmosphere . With the help of theory and observation the part played by this atmosphere is tolerably precise . Its absorptive effects upon the radiations of the inner photosphere can be readily traced progressively from the centre to the rim of the sun's disk, and it has been measured as a whole by Langley, W . E . Wilson and others, and for each separate wave-length by F . W . Very (Astrophys . Journ., vol. xvi.) . The entries in the table on following See also:

• PAGE
• PAGE, THOMAS NELSON (1853- )
• PAGE, WILLIAM (1811-1885)

page express the reduction of intensity for different wave-lengths a, when the slit is set at distances yXradius from the centre of the disk .

See also:

• BUILDING

Building upon these results A . Schuster has shown (Astrophys . Journ., vol. xvi.) that, if for the See also:

• SAKE

sake of See also:

• ARGUMENT

argument the solar atmosphere be taken as homogeneous in temperature and quality, forming a See also:

• SHEET

sheet which itself radiates as well as absorbs, the radiation which an unshielded ideal radiator at 6000° 'would give is represented well, both in sum and in the distribution of intensity with respect to wave-length, by another ideal radiator—now the actual body of (From (lstrophysical Journal, xvii. a, by permission: of the University of See also:

• CHICAGO
• CHICAGO, UNIVERSITY OF

Chicago See also:

• PRESS (through Fr. presse from Lat. pressare, frequentative of premere, to crush, squeeze, press)

Press.) condensing power of gravitation at the sun's borders is the pressure of radiation . The radiations from the sun must be considered in two parts, corresponding respectively to the continuous spectrum and the "The Black line-spectrum . The latter is considered below; Body." it is indicative of the chemical elements frcm which the sun—at about 6700°, shielded by an atmosphere at an average temperature of 5500°, and that such an atmosphere itself provides about 0.3 of the total radiations that reach us . In connexion with this subject it may be mentioned that the highest measured temperature produced terrestrially, that of the arc, is about 350o° to 4000° abs . X . 7=0.5 . 7=0.75 7 095 mm . 0'959 o•950 0.856 1500 1010 0.943 0'894 0'765 781 0.941 o•885 0.749 615 0.948 0.845 0.681 550 0.933 0.831 0.587 468 0.902 0.764 0.462 416 0.858 0.744 0'471 The energy which the sun pours out into space is, so far as we know, and except for the minute fraction intercepted by the disks See also:

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

Age of the of the See also:

• PLANETS, MINOR

planets (3~osssse) absolutely lost for the pur-Sun. poses of further mechanical effect . The amount is such that, supposing the average specific heat of the sun's body as high as that of water, there would result a general fall of temperature of 2.0° to 2.5° C. in the lapse of each year . Hence, if no other agency is invoked, at an See also:

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

epoch say xX1o0o years ago, the sun's heat would have been greater than now by the factor 1+x/3n, where nX6000° is taken for the sun's See also:

• PRESENT

present mean temperature .

It seems possible that n is not a large number, and if we take x equal, say, to 200, we come to the most See also:

• RECENT

recent estimate—the astronomical—of the date of the earth's glacial epoch, when the sun's radiation was certainly not much more than it is now, while this factor would differ materially from unity . Hence loss does not go on without regeneration, and we are apparently at a See also:

• STAGE (Fr. 6/age; from Lat. stare, to stand)

stage when there is an approximate balance between them . It is in fact an impossibility that loss should go on without regeneration, for if any part of the sun's body loses heat, it will be unable to support the pressure of neighbouring parts upon it; it will therefore be compressed, in a general sense towards the sun's centre, the velocities of its molecules will rise, and its temperature will again tend upwards . In consequence of the radiation of heat the whole body will be more condensed than before, but whether it is hotter or colder than before will depend on whether the contraction set up is more or less than enough to restore an exact balance . If we are dealing with comparatively recent periods there is no evidence of progressive change, but if we go to remote epochs and suppose the sup to have once been diffused in a nebulous state, it is clear that its shrinkage, in spite of radiation, has See also:

• LEFT

left it hotter, so that the shrinkage has outrun what would suffice to maintain its radiation . It is equally clear that there is a point beyond which contraction cannot go, and thereafter, if not before, the body will begin to grow colder . There is thus a turning-point in the life of every See also:

• STAR

star . The See also:

• MOVEMENT

movement towards contraction and consequent rise of temperature which radiation sets up, like other motions, overruns the equilibrium-point, only however by a minute amount; the accumulated excesses from all past time now stored in the sun would maintain its radiations at their present rate for nX3000 years, that is, for a few thousand years only . There is a See also:

• SUPERIOR

superior limit to the quantity of energy which can be derived from contraction . If we suppose the sun's mass once existed in a state of extreme See also:

• DIFFUSION (from the Lat. diffundere; dis-, asunder, and fundere, to pour out)

diffusion, the energy yielded by See also:

• COLLECTING

collecting it into its present See also:

• COMPASS (Fr. corn pas, ultimately from Lat. cum, with, and passus, step)

compass would not suffice to maintain its present rate of radiation for more than 17,000,000 years in the past; nor if its mean density were ultimately to rise to eight times its present amount, for more than the same period in the future . This supposes the present density nearly uniform; if it is not uniform, any amount added to the former period is subtracted from the latter . A contraction of 0.2" or 90 M. in the sun's radius would maintain the present emission for 3500 years .

Such a rate of change would be quite insensible, and we can affirm that for recent times there is no See also:

• REASON (Lat. ratio, through French raison)

reason to look for any other factor than contraction; but if we consider the remote past it is a different matter . We know nothing quantitatively of the radiations from a nebulous body; and it is quite possible that the loss of radiant energy in this See also:

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

early stage was very small; but it is at least as certain as any other physical inference that 17,000,000 years ago the earth itself was of its present dimensions, a comparatively old body with See also:

• SEA (in O. Eng. sae, a common Teutonic word; cf. Ger. See, Dutch Zee, &c.; the ultimate source is uncertain)
• SEA, COMMAND OF THE

sea and living creatures upon it, and it is impossible to believe that the sun's radiations were wholly different ;,but, if they were not, they have been maintained from some other source than contraction . The fall of meteoric matter into the sun must be a certain source of energy; if considerable, this See also:

• EXTERNAL

external See also:

• SUPPLY (through Fr. from Lat. supplere, to fill up)

supply would retard the sun's contraction and so increase its estimated age, but to bring about a reconciliation with See also:

• GEOLOGICAL

geological theory, very nearly the whole amount must be thus supplied . It is easy to calculate that this would be produced by an See also:

• ANNUAL

annual fall of matter equal to one nineteen millionth of the sun's mass, which would make an envelope eight metres thick, at the sun's mean density; this would be collectedduring the year from a spherical space extending beyond the See also:

• ORBIT (from Lat. orbita, a track, orbis, a wheel)

orbit of See also:

• JUPITER

Jupiter . The earth would intercept an amount of it proportional to the solid anile it subtends at the sun; that is to say, it would receive a See also:

• DEPOSIT (Lat. depositurn, from deponere, to lay down, to put in the care of)

deposit of meteoric matter about one-tenth of a millimetre, of density say 2, over its whole surface in the course of the year . So far there is nothing impossible in the theory . But there are two fatal objections . The sun is a small See also:

• TARGET
• TARGET, GUI JEAN BAPTISTE (1733-1807)

target for a See also:

• METEORITE

meteorite coming from infinity to See also:

• HIT

hit, and if this considerable quantity reaches its See also:

• MARK
• MARK, CARL (1858– )
• MARK, GOSPEL OF ST
• MARK, ST

mark, a much greater amount will circulate See also:

• ROUND (O. Fr. rond, Lat. rotundus, the Fr. is the source also of Du. rond; Ger., Swed., Dan. and Nor. rond)

round the sun in parabolas, and there is no evidence of it where it would certainly make itself See also:

• FELT (cognate with Ger. Filz, Du. vilt, Swed. and Dan. fill; the root is unknown; the word has given Med. Lat. filtrum, " filter ")

felt, in perturbations of the planets . A second objection is that it fails in its purpose, because 20,000,000 years ago it would give a sun quite as much changed as the contraction theory gave . If we examine chemical See also:

• SOURCES

sources for See also:

• MAINTENANCE (Fr. maintenance, from maintenir, to maintain, support, Lat. manu tenere, to hold in the hand)

maintenance of the sun's heat, See also:

• COMBUSTION (from the Lat. comburere, to burn up)

combustion and other forms of See also:

• COMBINATION (Lat. combinare, to combine)

combination are out of the question, because no combinations of different elements are known to exist at a temperature of 6000° . A source which seems plausible, perhaps only because it is less easy to test, is rearrangement of the structure of the elements' atoms . An See also:

• ATOM (Gr. &rows, indivisible, from a- privative, and TE,aPfw, to cut)

atom is no longer figured as indivisible, it is made up of more or less complex, and more or less permanent, systems in internal circulation .

Now under the law of attraction according to the inverse square of the distance, or any other inverse power beyond the first, the energy of even a single pair of material points is unlimited, if their possible closeness of approach to one another is unlimited . If the sources of energy within the atom can be See also:

• DRAWN

drawn upon, and the phenomena of radio-activity leave no doubt about this, there is here an incalculable source of heat which takes the cogency out of any other calculation respecting the sources maintaining the sun's radiation . An See also:

• EQUIVALENT

equivalent statement of the same conclusion may be put thus: supposing a gaseous nebula is destined to condense into a sun, the elementary matter of which it is composed will develop in the See also:

• PROCESS

process into our known terrestrial and solar elements, parting with energy as it does so . The continuous spectrum leads to no inference, except that of the temperature of the central globe; but the multitude of dark lines by which it is crossed reveal the elements composing Spectrum of the truly gaseous cloaks which enclose it . A table of the Sun . these lines is a physical document as exact as it is intricate . The visual portion extends from about w.1.3700 to 7200 - tenth-metres; the ultra-See also:

• VIOLET

violet begins about 2970, beyond which point our atmosphere is almost perfectly opaque to it; the infra-red can be traced for more than ten times the visual length, but the gaps which indicate absorption-lines have not been mapped beyond 9870 . The ultra-violet and the visual portion are re-corded photographically; See also:

• ROWLAND, HENRY AUGUSTUS (1848-1901)

Rowland's classical See also:

• WORK

work shows some 5700 lines in the former, and 14,200 in the latter, on a graduated See also:

• SCALE
• SCALE (1) A

scale of intensities from woo to o, or 0000, for the faintest lines; between a See also:

• QUARTER (through Fr. from Lat. quartarius, fourth part)

quarter and a third of these lines have been identified, fully 2000 belonging to See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron, and several See also:

• HUNDRED

hundred to water vapour and other atmospheric absorption . The infra-red requires See also:

• SPECIAL

special appliances; it has been examined visually by the help of phosphorescent plates (See also:

• BECQUEREL

Becquerel), and with special photographic plates (Abney) ; but the most efficient way is to use the bolometer or radiomicrometer; by this means some 500 or 600 lines have been mapped . The first problem of the spectrum is to identify the effects of atmospheric absorption, especially See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen, carbonic See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid and water vapour; this is done generally by comparing the spectra of the sun at great and small See also:

• ZENITH (from the Arabic)

zenith-distances, or by reducing the atmospheric effect by observing from a great See also:

• ELEVATION

elevation, as did P . J . C .

See also:

• JANSSEN, JOHANNES (1829-1891)
• JANSSEN, or JANSEN (sometimes JOHNSON), CORNELIUS (1593-1664)
• JANSSEN, PIERRE JULES CESAR (1824–1907)

Janssen from the See also:

• SUMMIT

summit of Mont See also:

• BLANC, (JEAN JOSEPH CHARLES) LOUIS (1811-1882)
• BLANC, MONT

Blanc, but the only unquestionable test is to find those lines which are not touched by Doppler effect when the receding and advancing limbs of the sun are compared (See also:

• CORNU, MARIE

Cornu) ; by this method H . F . Newall has verified the presence of See also:

• CYANOGEN (Gr. ebavos, blue 'yevvav, to produce), C2N2

cyanogen in the photosphere, and it had previously served to disprove the solar origin of certain oxygen lines . In fact, doubt long surrounded the presence of oxygen in the sun, and was not set at rest until K . D . T . Runge and F . Paschen in 1896 identified an unmistakable oxygen triplet in the infra-red, which is shown terrestrially only in the vacuum See also:

• TUBE (Lat. tuba)

tube, where the spectrum is very different from that of atmospheric absorptions . The See also:

• ABSENCE (Lat. absentia)

absence of lines of the spectrum of any See also:

• ELEMENT (Lat. elementum)

element from the solar spectrum is no See also:

• PROOF (in M. Eng. preove, proeve, preve, &°c., from O. Fr . prueve, proeve, &c., mod. preuve, Late. Lat. proba, probate, to prove, to test the goodness of anything, probus, good)

proof that the element is absent from the sun; apart from the possibility that the high temperature and other circumstances may show it trans-formed into some unknown mode, which is perhaps the explanation of the absence of See also:

• NITROGEN [symbol N., atomic weight 14.01, 0=16]

nitrogen, See also:

• CHLORINE (symbol Cl, atomic weight 35`46 (0=16)

chlorine and other non-metals; if the element is of high atomic See also:

• WEIGHT

weight we should expect it to be found only in the lowest strata of the sun's atmosphere, where its temperature was nearly equal to that of the central globe, and so any absorption line which it showed would be weak . This is undoubtedly the case with lead-and See also:

• SILVER

silver, and probably with See also:

• MERCURY
• MERCURY (MERCU1uus)
• MERCURY (symbol Hg, atomic weight = 2oo)

mercury also . In Rowland's table lines from the arc-spectra of the following are identified . 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 is approximately that of the See also:

• NUMBERS, BOOK OF
• NUMBERS, PARTITION OF

numbers of identified lines .

Excepting See also:

• STRONTIUM [Symbol Sr, atomic weight 87.62 (0=16)]

strontium, those which are low upon the See also:

• LIST (O.E. lisle, a Teutonic word, cf. Dut. lust, Ger. Leiste, adapted in Ital. lista and Fr. lisle)
• LIST, FRIEDRICH (1789-1846)

list are represented also by lines of small intensity . The chromosphere adds the three last of the list . The strongest lines are those due to See also:

• CALCIUM [symbol Ca, atomic weight 40.0 (o= x6)]

calcium, iron, hydrogen, See also:

• SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium, See also:

• NICKEL
• NICKEL (symbol Ni, atomic weight 58.68 (0=16))

nickel, in the order named . Iron Neodymium See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

Aluminium See also:

• BISMUTH

Bismuth (?) Nickel Lanthanum See also:

• CADMIUM (symbol Cd, atomic weight 112.4 (0=16))

Cadmium See also:

• TELLURIUM [Symbol Te, atomic weight 127.5 (0=16)]

Tellurium See also:

• TITANIUM [symbol Ti, atomic weight 48.1 (0 = 16)]

Titanium See also:

• YTTRIUM [symbol, Y; atomic weight, 89.0 (0 =16)]

Yttrium See also:

• RHODIUM [symbol Rh; atomic weight 102.9 (0=16)]

Rhodium See also:

• INDIUM (symbol In, atomic weight 114.8)

Indium See also:

• MANGANESE (symbol Mn; atomic weight, 54.93 (0=16)], a metallic chemical element. Its dioxide (pyrolusite)

Manganese Niobium See also:

• ERBIUM (symbol, Er; atomic weight, 165-166)

Erbium Oxygen See also:

• CHROMIUM (symbol Cr. atomic weight 52.1)

Chromium See also:

• MOLYBDENUM [symbol, Mo; atomic weight, 96 (0=16)]

Molybdenum See also:

• ZINC

Zinc See also:

• TUNGSTEN [symbol W, atomic weight 184.o (0=16)]

Tungsten See also:

• COBALT (symbol Co, atomic weight 59)

Cobalt See also:

• PALLADIUM (Gr. sraXXit&ov)
• PALLADIUM [symbol Pd, atomic weight Io6.7 (O=16)]

Palladium See also:

• COPPER (symbol Cu, atomic weight 63.1, H=1, or 63.6, O = 16)

Copper Mercury (?) Carbon See also:

• MAGNESIUM [symbol Mg, atomic weight 24.32 (0 = 16)]

Magnesium Silver See also:

• VANADIUM

Vanadium Sodium See also:

• GERMANIUM

Germanium See also:

• HELIUM (from Gr. i)Xcor, the sun)

Helium See also:

• ZIRCONIUM

Zirconium See also:

• SILICON [symbol Si, atomic weight 28.3 (0= 16)]

Silicon See also:

• GLUCINUM