*But not Zr.
ZIRCONIUM (40)
The ultimate lines of the zirconium atom[335]are all found in the solar spectrum, far into the ultra-violet.
The bands in the spectra of stars of Classare found to correspond with those of ZrO₂, zirconium oxide.[336]A comparisonof the furnace spectrum of zirconium oxide with that of titanium oxide, which produces the characteristic flutings in Class,indicates that titanium oxide persists to lower temperatures.[337]It is of interest to note that the only oxides, other than water, which have been detected in stellar spectra, are those of elements in the fourth column of the periodic table, namely carbon, titanium and zirconium. Probably this has a chemical interpretation. The presence of silicon dioxide SiO₂ has not been detected, although it might be anticipated.
NIOBIUM (41)
Rowland identifies some of the lines associated with niobium in the solar spectrum. The series relations are unknown, and the lines are too faint to be detected in stellar spectra.
MOLYBDENUM (42)
All the ultimate lines of molybdenum are present in the solar spectrum. They are too faint to be detected in the stars. The spectrum has been analyzed into series by Kiess,[338]and by Catalan.[339]
RUTHENIUM (44) RHODIUM (45) PALLADIUM (46)
The strongest lines in the spectra of the three lighter platinum metals are all present in the solar spectrum,[340]but are too faint to be traced in the spectra of stars. Series relations are as yet unknown. The heavier platinum metals, osmium (76), iridium (77), and platinum (78), are not certainly found in the solar spectrum.
SILVER (47)
The ultimate ()lines of silver are at 3281 and 3383. They are both faintly present in the solar spectrum. The doublet at 4669, 4476 ()is also probably present in the spectrum of the sun. The lines cannot be traced in stellar spectra.
TIN (50)
A line of neutral tin was reported by Lunt[341]in the spectrum ofScorpii. Series relations are as yet unknown. In view of the absence of identifications of related lines, the attribution cannot be regarded as very certain. The strongest line in the spectrum of ionized tin is stated by the same investigator to lie at 4585.80. This line is either absent from or exceedingly weak in the solar spectrum.
BARIUM (56)
Neutral barium is not certainly present in stellar spectra. The first two ultimate lines ()fall in the red and the ultra-violet respectively, and would therefore escape notice in the stars. No lines of corresponding wave-length appear in Rowland’s table, but they are found in sunspots.[342]Thegroups are also absent from the solar spectrum.
The strength of the barium lines in the sun has been thought by Russell to be abnormal, and the question has been considered by several investigators.[343][344][345]
IONIZED BARIUM
Ionized barium is represented by thelines which are present, though weak, in the sun, and by thelines, which appear[346]at,and increase in intensity for all cooler stars. Theline is at 4555, and its behavior is difficult to trace, as it is much blended.
THE RARE EARTHS (57-71)
The spectra of the rare earths are so rich in lines that spurious identifications with lines in stellar spectra are often likely to occur. Numerous attributions to lanthanum (57), cerium (58), andneodymium (60) are given in Rowland’s table. The occurrence of some of these elements has also been definitely established in the spectra of certain stars. Kiess[347]has demonstrated the presence of europium (63) and of terbium (65) inCanum Venaticorum. Numerous lines, identified with those of rare earth elements, are reported by Mitchell[348]in the chromospheric spectrum.
If the lines in the chromosphere and thestar are indeed derived from the rare earths, the atoms concerned must be at least singly ionized. No series relations have as yet been published for any rare earth element, excepting a short list of relative term values for lanthanum.[349]From analogy with the previous long period it would seem unlikely that the first ionization potential of these atoms can be as great as 13 volts, the value which would be required if the lines have a maximum intensity at.
LEAD (82)
A single line is attributed to lead in Rowland’s table.
RADIUM (88)
Giebeler and Küstner[350]suggested the occurrence of radium lines in the chromosphere. The identification was discussed by Dyson[351]and by Mitchell.[352]In the light of later knowledge it appears improbable that an element so heavy, and terrestrially so rare,[353]would be present in the sun at sufficient heights and in great enough quantity to appear in the flash spectrum. The identification is probably to be regarded as spurious.
ELEMENTS NOT DETECTED IN STELLAR SPECTRA
The table which follows contains a list of elements which are absent, or of doubtful occurrence. The rare earths are omitted from the list.
The elements marked “doubtful” in the list are those for which coincidences with very faint solar lines occur.[354]Twelve out of the twenty-nine elements enumerated are halogens, inert gases, or metalloids, and it is significant that all the elements of these groups are absent, with the sole exception of helium.
FOOTNOTES:[125]M. N. R. A. S., 83, 166, 1923;ibid., 84, 368, 1924.[126]Ap. J., 61, 38, 1925.[127]Wright, Lick Pub., 13, 242, 1918.[128]A. Fowler, M. N. R. A. S., 80, 692, 1920.[129]H. A., 91, 7, 1918.[130]Fairfield, H. C. 264, 1924.[131]H. C. 258, 1924.[132]Ibid.[133]Payne, Proc. N. Ac. Sci., 11, 192, 1925; Chapter XIII,p. 188.[134]Nature, 114, 86, 1924.[135]Personal letter.[136]Chapter IV,p. 51.[137]Mt. W. Contr. 262, 1922.[138]Fairfield, H. C. 264, 1924.[139]Lindblad, Ap. J., 59, 305, 1924.[140]Chapter XII,p. 168.[141]Ap. J., 29, 100, 1909.[142]Ap. J., 60, 1, 1924.[143]Atlas, p. 85, 1892.[144]Wright, Nature, 109, 810, 1920.[145]Chapter III,p. 43.[146]Pub. A. S. P., 32, 155, 1920.[147]Mitchell, Ap. J., 38, 431, 1913.[148]Phil. Trans., 197A, 381, 1901.[149]C. R., 114, 578, 1892.[150]Pub. Obs. Mich., 3, 256, 1923.[151]Payne, H. C. 256, 1924;ibid., 263, 1924.[152]Henry Draper Catalogue; criterion of class.[153]Lyman, Phys. Rev., 21, 202, 1923.[154]Payne, Nature, 113, 783, 1924.[155]Mitchell, Ap. J., 38, 407, 1913.[156]H. C. 263, 1924.[157]Pub. Dom. Ap. Obs., 1, 335, 1922.[158]Mt. W. Contr. 236, 1922.[159]Mt. W. Contr. p. 160, 236, 1922.[160]De Gramont, C. R., 171, 1106, 1920.[161]Naturwiss., 12, 139, 1924.[162]Quoted by de Forcrand.[163]C. R., 178, 1868, 1924.[164]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.[165]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 351, 1922.[166]Payne, H. C. 256, 1924.[167]Wright, Lick Pub., 13, 193, 1918.[168]W. W. Campbell, Ast. and Ap., 13, 448, 1894.[169]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.[170]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.[171]Wright, Lick Pub., 13, 193, 1918.[172]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.[173]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.[174]H. C. 263, 1924.[175]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.[176]D. R. Hartree, Proc. Camb. Phil. Soc., 22, 409, 1924.[177]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.[178]M. N. R. A. S., 77, 511, 1917.[179]Wright, Lick Pub., 13, 193, 1918.[180]Mulliken, Nature, 114, 858, 1924; Birge, Phys. Rev. 23, 294, 1924; Freundlich and Hocheim, Zeit. f. Phys., 26, 102, 1924.[181]Kayser, Handbuch der Spektroskopie, Vol. VII, 132, 1924.[182]Evershed, Kod. Bul. 36, 1913.[183]Lindblad, Mt. W. Contr. 228, 1922.[184]Shapley and Lindblad, H. C. 228, 1921.[185]Lindblad, Mt. W. Contr. 228, 1922.[186]Shapley, H. B. 805, 1924.[187]Mt. W. Contr. 228, 1922.[188]L. O. B. 329, 1919.[189]Rufus, Pub. Obs. Mich., 3, 257, 1923.[190]A. Fowler, M. N. R. A. S., 70, 176, 1909.[191]Evershed, M. N. R. A. S., 68, 16, 1907.[192]Pluvinel and Baldet, Ap. J., 34, 89, 1907.[193]Merton and Johnson, Proc. Roy. Soc., 103A, 383, 1923.[194]A. Fowler, M. N. R. A. S., 70, 176, 1909.[195]Hale, Ellerman, and Parkhurst, Yerkes Pub., 2, 253, 1903.[196]Shane, L. O. B. 329, 1919.[197]M. N. R. A. S., 70, 176 and 484, 1909.[198]Strutt, Proc. Phys. Soc. Lond., 23, 147, 1911.[199]Stead, Phil. Mag., 22, 727, 1911.[200]A. Fowler, M. N. R. A. S., 70, 176 and 484, 1909.[201]C. R., 177, 1205, 1923.[202]Pluvinel and Baldet, Ap. J., 34, 89, 1911.[203]M. N. R. A. S., 76, 640, 1916.[204]Chapter XIV,p. 167.[205]Fowler, Report on Series in Line Spectra, 164, 1922.[206]Smyth, Proc. Roy. Soc., 103A, 121, 1923.[207]Vegard, Videns. Skr., 1, nos. 8, 9, 10, 1923, where previous work is summarized.[208]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.[209]A. Fowler, M. N. R. A. S., 70, 484, 1909.[210]Seep. 61.[211]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.[212]Proc. Roy. Soc., 106A, 138, 1924.[213]Nature, 115, 382, 1925.[214]Lord Rayleigh, Proc. Roy. Soc., 100A, 367, 1921;ibid.101A, 312, 1922.[215]A. Fowler, Proc. Roy. Soc., 107A, 31, 1925.[216]Payne, H. C. 256, 1924.[217]Ruark, Mohler, Foote, and Chenault, Bur. Stan. Sci. Pap. 480, 1924.[218]Proc. Roy. Soc., 82A, 532, 1909.[219]Pub. Solar Phys. Comm., 1910.[220]Payne, H. C. 256, 1924.[221]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 356, 1922.[222]Paddock, Pub. A. S. P., 31, 54, 1919.[223]Plaskett, J. R. A. S. Can., 12, 350, 1918.[224]Baxandall, Pub. A. S. P., 311 297, 1919.[225]Wright, M. N. R. A. S., 81, 181, 1920.[226]Ibid.Pub. A. S. P., 32, 276, 1920.[227]Stratton, M. N. R. A. S., 79, 366, 1919.[228]Hopfield, Ap. J., 59, 114, 1924.[229]Runge and Paschen, Wied. An., 61, 641, 1897.[230]Curtis and Burns, unpub.[231]A. Fowler, Report, 167, 1922.[232]Ibid.[233]An. Cape Obs., 10, 5B, 1906.[234]Payne, H. C. 256, 1924.[235]Pub. Dom. Ap. Obs., 1, 325, 1922.[236]Henry Draper Catalogue, H. A., 91, 1918.[237]M. N. R. A. S., 77, 511, 1917.[238]Wright, Lick Pub., 13, 193, 1918.[239]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.[240]Payne, H. C. 256, 1924; Proc. N. Ac. Sci., 10, 322, 1924.[241]R. H. Fowler and Milne, M. N. R. A. S., 84, 499, 1924.[242]Cortie, Ap. J., 28, 379, 1908.[243]A. Fowler, M. N. R. A. S., 67, 530, 1907.[244]Proc. Roy. Soc., 93A, 577, 1917.[245]Riesenfeld and Beja, Medd. Vetens. Nobelinst., 6, 8, 1923.[246]Menzel, H. C. 258, 1924.[247]Heger, L. O. B. 326, 1918.[248]Heger, L. O. B. 337, 1922.[249]Luyten, Pub. A. S. P., 35, 175, 1923.[250]Menzel, H. C. 258, 1924.[251]de Gramont, C. R., 171, 1106, 1920.[252]H. H. Plaskett, Pub. Som. Ap. Obs., 1, 325, 1922.[253]Menzel, H. C. 258, 1924.[254]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325,1922.[255]Proc. Roy. Soc., 80A, 218, 1907.[256]Phil. Trans., 209A, 447, 1909.[257]M. N. R. A. S., 67, 530, 1908.[258]R. H. Fowler and Milne, M. N. R. A. S., 83, 403, 1923.[259]Menzel, H. C. 258, 1924; p. 122.[260]Adams and Joy, Pub. A. S. P., 36, 142, 1924.[261]Paschen, An. d. Phys., 71, 151, 1923.[262]Payne, H. C. 252, 1924.[263]Bakerian Lecture, 1924.[264]King, Pub. A. S. P., 33, 106, 1921.[265]de Gramont, C. R., 171 1106, 1920.[266]Payne, H. C. 252, 1924.[267]P. 169.[268]Payne, H. C. 252, 1924.[269]Bakerian Lecture, 1924.[270]Payne, H. C. 263, 1924.[271]Hopfield, Nature, 112, 437, 1923.[272]Proc. Roy. Soc., 80A, 50, 1907.[273]H. C. 256, 1924.[274]M. N. R. A. S., 84, 499, 1924.[275]Fowler, Report on Series in Line Spectra, 1922.[276]Curtis and Burns, unpub.[277]Personal letter.[278]Russell and Saunders, Ap. J., 61, 38, 1925.[279]Menzel, H. C. 258, 1924.[280]Ibid.[281]Adams and Joy, Pub. A. S. P., 36, 142, 1924.[282]Ap. J., 19, 268, 1904.[283]Lee, Ap. J., 37, 1, 1913.[284]Pub. Dom. Ap. Obs., 2, 16, 1924.[285]Heger, L. O. B. 326, 1918;ibid.337, 1922.[286]Rufus, J. R. A. S. Can., 14, 139, 1920.[287]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 344, 1924.[288]Russell, Mt. W. Contr., in press.[289]J. Op. Soc. Am., 9, 355, 1924.[290]Mt. W. Contr., in press.[291]J. Op. Soc. Am., 8, 609, 1924.[292]Payne, Proc. N. Ac. Sci., 11, 192, 1925.[293]Menzel, H. C. 258, 1924.[294]Chapter VII,p. 113.[295]Maury, H. A., 28, 79, 1900.[296]Russell, Mt. W. Contr., in press.[297]H. C. 258, 1924.[298]Chapter IX,p. 123.[299]loc. cit.[300]A. Fowler, Proc. Roy. Soc., 73A, 219, 1904; M. N. R. A. S., 69, 508, 1909.[301]Hale, Adams and Gale, Ap. J., 24, 185, 1906; Hale and Adams,ibid., 25, 75, 1907.[302]Rep. of Spectral Class. Comm., I. A. U., 1925.[303]W. F. Meggers, J. Wash. Ac. Sci., 13, 317, 1923;ibid., 14, 151, 1924.[304]Menzel, H. C. 258, 1924.[305]Ap. J., 25, 235, 1907.[306]J. Op. Soc. Am., 9, 355, 1924.[307]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84, 1923.[308]Russell, Mt. W. Contr., in press.[309]Chapter VIII,p. 124.[310]Menzel, H. C. 258, 1924.[311]J. Op. Soc. Am., 9, 335, 1924.[312]Catalan, Phil. Trans., 223A, 127, 1922.[313]Chapter VIII,p. 124.[314]H. C. 238, 1924.[315]J. Op. Soc. Am., 9, 355, 1924.[316]Phil. Trans., 223A, 127, 1922.[317]Walters, J. Op. Soc. Am., 8, 245, 1924.[318]Chapter VIII,p. 125.[319]Ibid.[320]Pub. Dom. Ap. Obs., 3, 7, 1925.[321]H. C. 258, 1924.[322]Chapter VIII,p. 126.[323]Mt. W. Contr., in press.[324]Walters, J. Wash. Ac. Sci., 14, 408, 1924.[325]Russell, Ap. J., 55, 119, 1922.[326]Menzel, H. C. 258, 1924.[327]Ap. J., 9, 214, 1899.[328]Russell, Ap. J., 55, 119, 1922.[329]Menzel, H. C. 258, 1924.[330]Chapter VIII,p. 126.[331]Chapter XII,p. 169.[332]Pub. Dom. Ap. Obs., 2, 287, 1924.[333]Meggers, J. Wash. Ac. Sci., 14, 419, 1924.[334]Ibid.[335]de Gramont, C. R., 171, 1106, 1920.[336]Merrill, Pub. A. S. P., 33, 206, 1921.[337]King, Pub. A. S. P., 36, 140, 1924.[338]Kiess, Bur. Stan. Sci. Pap. 474, 1924.[339]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84 and 213, 1923.[340]Russell, Science, 39, 791, 1914.[341]M. N. R. A. S., 77, 487, 1907.[342]Russell, Ap. J., 55, 119, 1922.[343]Saha, Phil. Mag., 40, 472, 1920.[344]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.[345]M. C. Johnson, M. N. R. A. S., 84, 516, 1924.[346]Menzel, H. C. 258, 1924.[347]Kiess, Pub. Obs. Mich., 3, 106, 1923.[348]Mitchell, Ap. J., 38, 407, 1913.[349]Gousmid, Naturwiss., 41, 851, 1924.[350]A. N., 191, 393, 1912.[351]A. N., 192, 82, 1912.[352]A. N., 192, 266, 1912.[353]Chapter I,p. 5.[354]Abbot, The Sun, 92, 1911.
[125]M. N. R. A. S., 83, 166, 1923;ibid., 84, 368, 1924.
[125]M. N. R. A. S., 83, 166, 1923;ibid., 84, 368, 1924.
[126]Ap. J., 61, 38, 1925.
[126]Ap. J., 61, 38, 1925.
[127]Wright, Lick Pub., 13, 242, 1918.
[127]Wright, Lick Pub., 13, 242, 1918.
[128]A. Fowler, M. N. R. A. S., 80, 692, 1920.
[128]A. Fowler, M. N. R. A. S., 80, 692, 1920.
[129]H. A., 91, 7, 1918.
[129]H. A., 91, 7, 1918.
[130]Fairfield, H. C. 264, 1924.
[130]Fairfield, H. C. 264, 1924.
[131]H. C. 258, 1924.
[131]H. C. 258, 1924.
[132]Ibid.
[132]Ibid.
[133]Payne, Proc. N. Ac. Sci., 11, 192, 1925; Chapter XIII,p. 188.
[133]Payne, Proc. N. Ac. Sci., 11, 192, 1925; Chapter XIII,p. 188.
[134]Nature, 114, 86, 1924.
[134]Nature, 114, 86, 1924.
[135]Personal letter.
[135]Personal letter.
[136]Chapter IV,p. 51.
[136]Chapter IV,p. 51.
[137]Mt. W. Contr. 262, 1922.
[137]Mt. W. Contr. 262, 1922.
[138]Fairfield, H. C. 264, 1924.
[138]Fairfield, H. C. 264, 1924.
[139]Lindblad, Ap. J., 59, 305, 1924.
[139]Lindblad, Ap. J., 59, 305, 1924.
[140]Chapter XII,p. 168.
[140]Chapter XII,p. 168.
[141]Ap. J., 29, 100, 1909.
[141]Ap. J., 29, 100, 1909.
[142]Ap. J., 60, 1, 1924.
[142]Ap. J., 60, 1, 1924.
[143]Atlas, p. 85, 1892.
[143]Atlas, p. 85, 1892.
[144]Wright, Nature, 109, 810, 1920.
[144]Wright, Nature, 109, 810, 1920.
[145]Chapter III,p. 43.
[145]Chapter III,p. 43.
[146]Pub. A. S. P., 32, 155, 1920.
[146]Pub. A. S. P., 32, 155, 1920.
[147]Mitchell, Ap. J., 38, 431, 1913.
[147]Mitchell, Ap. J., 38, 431, 1913.
[148]Phil. Trans., 197A, 381, 1901.
[148]Phil. Trans., 197A, 381, 1901.
[149]C. R., 114, 578, 1892.
[149]C. R., 114, 578, 1892.
[150]Pub. Obs. Mich., 3, 256, 1923.
[150]Pub. Obs. Mich., 3, 256, 1923.
[151]Payne, H. C. 256, 1924;ibid., 263, 1924.
[151]Payne, H. C. 256, 1924;ibid., 263, 1924.
[152]Henry Draper Catalogue; criterion of class.
[152]Henry Draper Catalogue; criterion of class.
[153]Lyman, Phys. Rev., 21, 202, 1923.
[153]Lyman, Phys. Rev., 21, 202, 1923.
[154]Payne, Nature, 113, 783, 1924.
[154]Payne, Nature, 113, 783, 1924.
[155]Mitchell, Ap. J., 38, 407, 1913.
[155]Mitchell, Ap. J., 38, 407, 1913.
[156]H. C. 263, 1924.
[156]H. C. 263, 1924.
[157]Pub. Dom. Ap. Obs., 1, 335, 1922.
[157]Pub. Dom. Ap. Obs., 1, 335, 1922.
[158]Mt. W. Contr. 236, 1922.
[158]Mt. W. Contr. 236, 1922.
[159]Mt. W. Contr. p. 160, 236, 1922.
[159]Mt. W. Contr. p. 160, 236, 1922.
[160]De Gramont, C. R., 171, 1106, 1920.
[160]De Gramont, C. R., 171, 1106, 1920.
[161]Naturwiss., 12, 139, 1924.
[161]Naturwiss., 12, 139, 1924.
[162]Quoted by de Forcrand.
[162]Quoted by de Forcrand.
[163]C. R., 178, 1868, 1924.
[163]C. R., 178, 1868, 1924.
[164]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.
[164]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.
[165]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 351, 1922.
[165]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 351, 1922.
[166]Payne, H. C. 256, 1924.
[166]Payne, H. C. 256, 1924.
[167]Wright, Lick Pub., 13, 193, 1918.
[167]Wright, Lick Pub., 13, 193, 1918.
[168]W. W. Campbell, Ast. and Ap., 13, 448, 1894.
[168]W. W. Campbell, Ast. and Ap., 13, 448, 1894.
[169]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.
[169]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.
[170]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.
[170]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.
[171]Wright, Lick Pub., 13, 193, 1918.
[171]Wright, Lick Pub., 13, 193, 1918.
[172]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.
[172]T. R. Merton, Proc. Roy. Soc., 91A, 498, 1915.
[173]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.
[173]A. Fowler, Proc. Roy. Soc., 105A, 299, 1924.
[174]H. C. 263, 1924.
[174]H. C. 263, 1924.
[175]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.
[175]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.
[176]D. R. Hartree, Proc. Camb. Phil. Soc., 22, 409, 1924.
[176]D. R. Hartree, Proc. Camb. Phil. Soc., 22, 409, 1924.
[177]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.
[177]R. H. Fowler and Milne, M. N. R. A. S., 84, 502, 1924.
[178]M. N. R. A. S., 77, 511, 1917.
[178]M. N. R. A. S., 77, 511, 1917.
[179]Wright, Lick Pub., 13, 193, 1918.
[179]Wright, Lick Pub., 13, 193, 1918.
[180]Mulliken, Nature, 114, 858, 1924; Birge, Phys. Rev. 23, 294, 1924; Freundlich and Hocheim, Zeit. f. Phys., 26, 102, 1924.
[180]Mulliken, Nature, 114, 858, 1924; Birge, Phys. Rev. 23, 294, 1924; Freundlich and Hocheim, Zeit. f. Phys., 26, 102, 1924.
[181]Kayser, Handbuch der Spektroskopie, Vol. VII, 132, 1924.
[181]Kayser, Handbuch der Spektroskopie, Vol. VII, 132, 1924.
[182]Evershed, Kod. Bul. 36, 1913.
[182]Evershed, Kod. Bul. 36, 1913.
[183]Lindblad, Mt. W. Contr. 228, 1922.
[183]Lindblad, Mt. W. Contr. 228, 1922.
[184]Shapley and Lindblad, H. C. 228, 1921.
[184]Shapley and Lindblad, H. C. 228, 1921.
[185]Lindblad, Mt. W. Contr. 228, 1922.
[185]Lindblad, Mt. W. Contr. 228, 1922.
[186]Shapley, H. B. 805, 1924.
[186]Shapley, H. B. 805, 1924.
[187]Mt. W. Contr. 228, 1922.
[187]Mt. W. Contr. 228, 1922.
[188]L. O. B. 329, 1919.
[188]L. O. B. 329, 1919.
[189]Rufus, Pub. Obs. Mich., 3, 257, 1923.
[189]Rufus, Pub. Obs. Mich., 3, 257, 1923.
[190]A. Fowler, M. N. R. A. S., 70, 176, 1909.
[190]A. Fowler, M. N. R. A. S., 70, 176, 1909.
[191]Evershed, M. N. R. A. S., 68, 16, 1907.
[191]Evershed, M. N. R. A. S., 68, 16, 1907.
[192]Pluvinel and Baldet, Ap. J., 34, 89, 1907.
[192]Pluvinel and Baldet, Ap. J., 34, 89, 1907.
[193]Merton and Johnson, Proc. Roy. Soc., 103A, 383, 1923.
[193]Merton and Johnson, Proc. Roy. Soc., 103A, 383, 1923.
[194]A. Fowler, M. N. R. A. S., 70, 176, 1909.
[194]A. Fowler, M. N. R. A. S., 70, 176, 1909.
[195]Hale, Ellerman, and Parkhurst, Yerkes Pub., 2, 253, 1903.
[195]Hale, Ellerman, and Parkhurst, Yerkes Pub., 2, 253, 1903.
[196]Shane, L. O. B. 329, 1919.
[196]Shane, L. O. B. 329, 1919.
[197]M. N. R. A. S., 70, 176 and 484, 1909.
[197]M. N. R. A. S., 70, 176 and 484, 1909.
[198]Strutt, Proc. Phys. Soc. Lond., 23, 147, 1911.
[198]Strutt, Proc. Phys. Soc. Lond., 23, 147, 1911.
[199]Stead, Phil. Mag., 22, 727, 1911.
[199]Stead, Phil. Mag., 22, 727, 1911.
[200]A. Fowler, M. N. R. A. S., 70, 176 and 484, 1909.
[200]A. Fowler, M. N. R. A. S., 70, 176 and 484, 1909.
[201]C. R., 177, 1205, 1923.
[201]C. R., 177, 1205, 1923.
[202]Pluvinel and Baldet, Ap. J., 34, 89, 1911.
[202]Pluvinel and Baldet, Ap. J., 34, 89, 1911.
[203]M. N. R. A. S., 76, 640, 1916.
[203]M. N. R. A. S., 76, 640, 1916.
[204]Chapter XIV,p. 167.
[204]Chapter XIV,p. 167.
[205]Fowler, Report on Series in Line Spectra, 164, 1922.
[205]Fowler, Report on Series in Line Spectra, 164, 1922.
[206]Smyth, Proc. Roy. Soc., 103A, 121, 1923.
[206]Smyth, Proc. Roy. Soc., 103A, 121, 1923.
[207]Vegard, Videns. Skr., 1, nos. 8, 9, 10, 1923, where previous work is summarized.
[207]Vegard, Videns. Skr., 1, nos. 8, 9, 10, 1923, where previous work is summarized.
[208]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.
[208]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.
[209]A. Fowler, M. N. R. A. S., 70, 484, 1909.
[209]A. Fowler, M. N. R. A. S., 70, 484, 1909.
[210]Seep. 61.
[210]Seep. 61.
[211]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.
[211]Vegard, Proc. Amst. Ac., 27, 1 and 2, 1924.
[212]Proc. Roy. Soc., 106A, 138, 1924.
[212]Proc. Roy. Soc., 106A, 138, 1924.
[213]Nature, 115, 382, 1925.
[213]Nature, 115, 382, 1925.
[214]Lord Rayleigh, Proc. Roy. Soc., 100A, 367, 1921;ibid.101A, 312, 1922.
[214]Lord Rayleigh, Proc. Roy. Soc., 100A, 367, 1921;ibid.101A, 312, 1922.
[215]A. Fowler, Proc. Roy. Soc., 107A, 31, 1925.
[215]A. Fowler, Proc. Roy. Soc., 107A, 31, 1925.
[216]Payne, H. C. 256, 1924.
[216]Payne, H. C. 256, 1924.
[217]Ruark, Mohler, Foote, and Chenault, Bur. Stan. Sci. Pap. 480, 1924.
[217]Ruark, Mohler, Foote, and Chenault, Bur. Stan. Sci. Pap. 480, 1924.
[218]Proc. Roy. Soc., 82A, 532, 1909.
[218]Proc. Roy. Soc., 82A, 532, 1909.
[219]Pub. Solar Phys. Comm., 1910.
[219]Pub. Solar Phys. Comm., 1910.
[220]Payne, H. C. 256, 1924.
[220]Payne, H. C. 256, 1924.
[221]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 356, 1922.
[221]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 356, 1922.
[222]Paddock, Pub. A. S. P., 31, 54, 1919.
[222]Paddock, Pub. A. S. P., 31, 54, 1919.
[223]Plaskett, J. R. A. S. Can., 12, 350, 1918.
[223]Plaskett, J. R. A. S. Can., 12, 350, 1918.
[224]Baxandall, Pub. A. S. P., 311 297, 1919.
[224]Baxandall, Pub. A. S. P., 311 297, 1919.
[225]Wright, M. N. R. A. S., 81, 181, 1920.
[225]Wright, M. N. R. A. S., 81, 181, 1920.
[226]Ibid.Pub. A. S. P., 32, 276, 1920.
[226]Ibid.Pub. A. S. P., 32, 276, 1920.
[227]Stratton, M. N. R. A. S., 79, 366, 1919.
[227]Stratton, M. N. R. A. S., 79, 366, 1919.
[228]Hopfield, Ap. J., 59, 114, 1924.
[228]Hopfield, Ap. J., 59, 114, 1924.
[229]Runge and Paschen, Wied. An., 61, 641, 1897.
[229]Runge and Paschen, Wied. An., 61, 641, 1897.
[230]Curtis and Burns, unpub.
[230]Curtis and Burns, unpub.
[231]A. Fowler, Report, 167, 1922.
[231]A. Fowler, Report, 167, 1922.
[232]Ibid.
[232]Ibid.
[233]An. Cape Obs., 10, 5B, 1906.
[233]An. Cape Obs., 10, 5B, 1906.
[234]Payne, H. C. 256, 1924.
[234]Payne, H. C. 256, 1924.
[235]Pub. Dom. Ap. Obs., 1, 325, 1922.
[235]Pub. Dom. Ap. Obs., 1, 325, 1922.
[236]Henry Draper Catalogue, H. A., 91, 1918.
[236]Henry Draper Catalogue, H. A., 91, 1918.
[237]M. N. R. A. S., 77, 511, 1917.
[237]M. N. R. A. S., 77, 511, 1917.
[238]Wright, Lick Pub., 13, 193, 1918.
[238]Wright, Lick Pub., 13, 193, 1918.
[239]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.
[239]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.
[240]Payne, H. C. 256, 1924; Proc. N. Ac. Sci., 10, 322, 1924.
[240]Payne, H. C. 256, 1924; Proc. N. Ac. Sci., 10, 322, 1924.
[241]R. H. Fowler and Milne, M. N. R. A. S., 84, 499, 1924.
[241]R. H. Fowler and Milne, M. N. R. A. S., 84, 499, 1924.
[242]Cortie, Ap. J., 28, 379, 1908.
[242]Cortie, Ap. J., 28, 379, 1908.
[243]A. Fowler, M. N. R. A. S., 67, 530, 1907.
[243]A. Fowler, M. N. R. A. S., 67, 530, 1907.
[244]Proc. Roy. Soc., 93A, 577, 1917.
[244]Proc. Roy. Soc., 93A, 577, 1917.
[245]Riesenfeld and Beja, Medd. Vetens. Nobelinst., 6, 8, 1923.
[245]Riesenfeld and Beja, Medd. Vetens. Nobelinst., 6, 8, 1923.
[246]Menzel, H. C. 258, 1924.
[246]Menzel, H. C. 258, 1924.
[247]Heger, L. O. B. 326, 1918.
[247]Heger, L. O. B. 326, 1918.
[248]Heger, L. O. B. 337, 1922.
[248]Heger, L. O. B. 337, 1922.
[249]Luyten, Pub. A. S. P., 35, 175, 1923.
[249]Luyten, Pub. A. S. P., 35, 175, 1923.
[250]Menzel, H. C. 258, 1924.
[250]Menzel, H. C. 258, 1924.
[251]de Gramont, C. R., 171, 1106, 1920.
[251]de Gramont, C. R., 171, 1106, 1920.
[252]H. H. Plaskett, Pub. Som. Ap. Obs., 1, 325, 1922.
[252]H. H. Plaskett, Pub. Som. Ap. Obs., 1, 325, 1922.
[253]Menzel, H. C. 258, 1924.
[253]Menzel, H. C. 258, 1924.
[254]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325,1922.
[254]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325,1922.
[255]Proc. Roy. Soc., 80A, 218, 1907.
[255]Proc. Roy. Soc., 80A, 218, 1907.
[256]Phil. Trans., 209A, 447, 1909.
[256]Phil. Trans., 209A, 447, 1909.
[257]M. N. R. A. S., 67, 530, 1908.
[257]M. N. R. A. S., 67, 530, 1908.
[258]R. H. Fowler and Milne, M. N. R. A. S., 83, 403, 1923.
[258]R. H. Fowler and Milne, M. N. R. A. S., 83, 403, 1923.
[259]Menzel, H. C. 258, 1924; p. 122.
[259]Menzel, H. C. 258, 1924; p. 122.
[260]Adams and Joy, Pub. A. S. P., 36, 142, 1924.
[260]Adams and Joy, Pub. A. S. P., 36, 142, 1924.
[261]Paschen, An. d. Phys., 71, 151, 1923.
[261]Paschen, An. d. Phys., 71, 151, 1923.
[262]Payne, H. C. 252, 1924.
[262]Payne, H. C. 252, 1924.
[263]Bakerian Lecture, 1924.
[263]Bakerian Lecture, 1924.
[264]King, Pub. A. S. P., 33, 106, 1921.
[264]King, Pub. A. S. P., 33, 106, 1921.
[265]de Gramont, C. R., 171 1106, 1920.
[265]de Gramont, C. R., 171 1106, 1920.
[266]Payne, H. C. 252, 1924.
[266]Payne, H. C. 252, 1924.
[267]P. 169.
[267]P. 169.
[268]Payne, H. C. 252, 1924.
[268]Payne, H. C. 252, 1924.
[269]Bakerian Lecture, 1924.
[269]Bakerian Lecture, 1924.
[270]Payne, H. C. 263, 1924.
[270]Payne, H. C. 263, 1924.
[271]Hopfield, Nature, 112, 437, 1923.
[271]Hopfield, Nature, 112, 437, 1923.
[272]Proc. Roy. Soc., 80A, 50, 1907.
[272]Proc. Roy. Soc., 80A, 50, 1907.
[273]H. C. 256, 1924.
[273]H. C. 256, 1924.
[274]M. N. R. A. S., 84, 499, 1924.
[274]M. N. R. A. S., 84, 499, 1924.
[275]Fowler, Report on Series in Line Spectra, 1922.
[275]Fowler, Report on Series in Line Spectra, 1922.
[276]Curtis and Burns, unpub.
[276]Curtis and Burns, unpub.
[277]Personal letter.
[277]Personal letter.
[278]Russell and Saunders, Ap. J., 61, 38, 1925.
[278]Russell and Saunders, Ap. J., 61, 38, 1925.
[279]Menzel, H. C. 258, 1924.
[279]Menzel, H. C. 258, 1924.
[280]Ibid.
[280]Ibid.
[281]Adams and Joy, Pub. A. S. P., 36, 142, 1924.
[281]Adams and Joy, Pub. A. S. P., 36, 142, 1924.
[282]Ap. J., 19, 268, 1904.
[282]Ap. J., 19, 268, 1904.
[283]Lee, Ap. J., 37, 1, 1913.
[283]Lee, Ap. J., 37, 1, 1913.
[284]Pub. Dom. Ap. Obs., 2, 16, 1924.
[284]Pub. Dom. Ap. Obs., 2, 16, 1924.
[285]Heger, L. O. B. 326, 1918;ibid.337, 1922.
[285]Heger, L. O. B. 326, 1918;ibid.337, 1922.
[286]Rufus, J. R. A. S. Can., 14, 139, 1920.
[286]Rufus, J. R. A. S. Can., 14, 139, 1920.
[287]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 344, 1924.
[287]J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 344, 1924.
[288]Russell, Mt. W. Contr., in press.
[288]Russell, Mt. W. Contr., in press.
[289]J. Op. Soc. Am., 9, 355, 1924.
[289]J. Op. Soc. Am., 9, 355, 1924.
[290]Mt. W. Contr., in press.
[290]Mt. W. Contr., in press.
[291]J. Op. Soc. Am., 8, 609, 1924.
[291]J. Op. Soc. Am., 8, 609, 1924.
[292]Payne, Proc. N. Ac. Sci., 11, 192, 1925.
[292]Payne, Proc. N. Ac. Sci., 11, 192, 1925.
[293]Menzel, H. C. 258, 1924.
[293]Menzel, H. C. 258, 1924.
[294]Chapter VII,p. 113.
[294]Chapter VII,p. 113.
[295]Maury, H. A., 28, 79, 1900.
[295]Maury, H. A., 28, 79, 1900.
[296]Russell, Mt. W. Contr., in press.
[296]Russell, Mt. W. Contr., in press.
[297]H. C. 258, 1924.
[297]H. C. 258, 1924.
[298]Chapter IX,p. 123.
[298]Chapter IX,p. 123.
[299]loc. cit.
[299]loc. cit.
[300]A. Fowler, Proc. Roy. Soc., 73A, 219, 1904; M. N. R. A. S., 69, 508, 1909.
[300]A. Fowler, Proc. Roy. Soc., 73A, 219, 1904; M. N. R. A. S., 69, 508, 1909.
[301]Hale, Adams and Gale, Ap. J., 24, 185, 1906; Hale and Adams,ibid., 25, 75, 1907.
[301]Hale, Adams and Gale, Ap. J., 24, 185, 1906; Hale and Adams,ibid., 25, 75, 1907.
[302]Rep. of Spectral Class. Comm., I. A. U., 1925.
[302]Rep. of Spectral Class. Comm., I. A. U., 1925.
[303]W. F. Meggers, J. Wash. Ac. Sci., 13, 317, 1923;ibid., 14, 151, 1924.
[303]W. F. Meggers, J. Wash. Ac. Sci., 13, 317, 1923;ibid., 14, 151, 1924.
[304]Menzel, H. C. 258, 1924.
[304]Menzel, H. C. 258, 1924.
[305]Ap. J., 25, 235, 1907.
[305]Ap. J., 25, 235, 1907.
[306]J. Op. Soc. Am., 9, 355, 1924.
[306]J. Op. Soc. Am., 9, 355, 1924.
[307]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84, 1923.
[307]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84, 1923.
[308]Russell, Mt. W. Contr., in press.
[308]Russell, Mt. W. Contr., in press.
[309]Chapter VIII,p. 124.
[309]Chapter VIII,p. 124.
[310]Menzel, H. C. 258, 1924.
[310]Menzel, H. C. 258, 1924.
[311]J. Op. Soc. Am., 9, 335, 1924.
[311]J. Op. Soc. Am., 9, 335, 1924.
[312]Catalan, Phil. Trans., 223A, 127, 1922.
[312]Catalan, Phil. Trans., 223A, 127, 1922.
[313]Chapter VIII,p. 124.
[313]Chapter VIII,p. 124.
[314]H. C. 238, 1924.
[314]H. C. 238, 1924.
[315]J. Op. Soc. Am., 9, 355, 1924.
[315]J. Op. Soc. Am., 9, 355, 1924.
[316]Phil. Trans., 223A, 127, 1922.
[316]Phil. Trans., 223A, 127, 1922.
[317]Walters, J. Op. Soc. Am., 8, 245, 1924.
[317]Walters, J. Op. Soc. Am., 8, 245, 1924.
[318]Chapter VIII,p. 125.
[318]Chapter VIII,p. 125.
[319]Ibid.
[319]Ibid.
[320]Pub. Dom. Ap. Obs., 3, 7, 1925.
[320]Pub. Dom. Ap. Obs., 3, 7, 1925.
[321]H. C. 258, 1924.
[321]H. C. 258, 1924.
[322]Chapter VIII,p. 126.
[322]Chapter VIII,p. 126.
[323]Mt. W. Contr., in press.
[323]Mt. W. Contr., in press.
[324]Walters, J. Wash. Ac. Sci., 14, 408, 1924.
[324]Walters, J. Wash. Ac. Sci., 14, 408, 1924.
[325]Russell, Ap. J., 55, 119, 1922.
[325]Russell, Ap. J., 55, 119, 1922.
[326]Menzel, H. C. 258, 1924.
[326]Menzel, H. C. 258, 1924.
[327]Ap. J., 9, 214, 1899.
[327]Ap. J., 9, 214, 1899.
[328]Russell, Ap. J., 55, 119, 1922.
[328]Russell, Ap. J., 55, 119, 1922.
[329]Menzel, H. C. 258, 1924.
[329]Menzel, H. C. 258, 1924.
[330]Chapter VIII,p. 126.
[330]Chapter VIII,p. 126.
[331]Chapter XII,p. 169.
[331]Chapter XII,p. 169.
[332]Pub. Dom. Ap. Obs., 2, 287, 1924.
[332]Pub. Dom. Ap. Obs., 2, 287, 1924.
[333]Meggers, J. Wash. Ac. Sci., 14, 419, 1924.
[333]Meggers, J. Wash. Ac. Sci., 14, 419, 1924.
[334]Ibid.
[334]Ibid.
[335]de Gramont, C. R., 171, 1106, 1920.
[335]de Gramont, C. R., 171, 1106, 1920.
[336]Merrill, Pub. A. S. P., 33, 206, 1921.
[336]Merrill, Pub. A. S. P., 33, 206, 1921.
[337]King, Pub. A. S. P., 36, 140, 1924.
[337]King, Pub. A. S. P., 36, 140, 1924.
[338]Kiess, Bur. Stan. Sci. Pap. 474, 1924.
[338]Kiess, Bur. Stan. Sci. Pap. 474, 1924.
[339]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84 and 213, 1923.
[339]Catalan, An. Soc. Espan. Fis. y Quim., 21, 84 and 213, 1923.
[340]Russell, Science, 39, 791, 1914.
[340]Russell, Science, 39, 791, 1914.
[341]M. N. R. A. S., 77, 487, 1907.
[341]M. N. R. A. S., 77, 487, 1907.
[342]Russell, Ap. J., 55, 119, 1922.
[342]Russell, Ap. J., 55, 119, 1922.
[343]Saha, Phil. Mag., 40, 472, 1920.
[343]Saha, Phil. Mag., 40, 472, 1920.
[344]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.
[344]H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.
[345]M. C. Johnson, M. N. R. A. S., 84, 516, 1924.
[345]M. C. Johnson, M. N. R. A. S., 84, 516, 1924.
[346]Menzel, H. C. 258, 1924.
[346]Menzel, H. C. 258, 1924.
[347]Kiess, Pub. Obs. Mich., 3, 106, 1923.
[347]Kiess, Pub. Obs. Mich., 3, 106, 1923.
[348]Mitchell, Ap. J., 38, 407, 1913.
[348]Mitchell, Ap. J., 38, 407, 1913.
[349]Gousmid, Naturwiss., 41, 851, 1924.
[349]Gousmid, Naturwiss., 41, 851, 1924.
[350]A. N., 191, 393, 1912.
[350]A. N., 191, 393, 1912.
[351]A. N., 192, 82, 1912.
[351]A. N., 192, 82, 1912.
[352]A. N., 192, 266, 1912.
[352]A. N., 192, 266, 1912.
[353]Chapter I,p. 5.
[353]Chapter I,p. 5.
[354]Abbot, The Sun, 92, 1911.
[354]Abbot, The Sun, 92, 1911.