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  63. T. T. Snith, this journal,  17, p. 145; 1928.
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  81. A. L. Schoen, this journal,  14, p. 179; 1927.
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  89. Ibid.G. R. Harrison, this journal,  11, p. 113; 1925.
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  92. H. C. Webster, Proc. Phys. Soc. Lond.,  41, p. 181; 1929. H. T. Meyer, Wissenschaftliche Veröffentlichung aus dem Siemans-Konzern, 7te Band, 2 Heft, p. 109. A. Bowers, ZS. für Phys.,  14, p. 174, 1923; Physica,  3, p. 113, 1923; ibid., 5, p. 8, 1925. Diss. Utrecht1924. R. Glocker and W. Traub, Phys. ZS. 22, p. 345; 1921.
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  94. H. B. Dorgelo, Phys. ZS.,  26, p. 790; 1925.

1929 (4)

See A. C. Hardy, this journal,  18, p. 96; 1929. K. S. Gibson, this journal,  7, p. 693; 1923.

G. R. Harrison, this journal,  18, p. 492; 1929.
[Crossref]

G. R. Harrison and H. Engwicht, this journal,  18, p. 287; 1929. (See also refs. 17, 18, 20, and 38.)

H. C. Webster, Proc. Phys. Soc. Lond.,  41, p. 181; 1929. H. T. Meyer, Wissenschaftliche Veröffentlichung aus dem Siemans-Konzern, 7te Band, 2 Heft, p. 109. A. Bowers, ZS. für Phys.,  14, p. 174, 1923; Physica,  3, p. 113, 1923; ibid., 5, p. 8, 1925. Diss. Utrecht1924. R. Glocker and W. Traub, Phys. ZS. 22, p. 345; 1921.

1928 (8)

T. Abe, Mazda Kenkyu-Jiho,  3, p. 325; 1928. (In English.)

O. Bloch and H. Horton, Phot. Jour.,  68, p. 352; 1928.

G. R. Harrison, this journal,  16, p. 63; 1928.
[Crossref]

T. T. Snith, this journal,  17, p. 145; 1928.
[Crossref]

W. T. Anderson, H. D. Frazer, and L. F. Bird, this journal,  17, p. 454; 1928.

H. C. v. Alphen, Ann. der Phys.,  85, p. 1058; 1928.

W. E. Forsythe, this journal,  16, p. 307; 1928.

G. R. Harrison, this journal,  17, p. 389; 1928.

1927 (9)

C. E. Weinland, this journal,  15, p. 337; 1927 (refs.).

R. W. Ditchburn, Camb. Phil. Soc. Proc.,  23, p. 959; 1927.

L. S. Ornstein and M. Minnaert, ZS. fur Phys.,  43, p. 404; 1927.

C. E. Wienland, this journal,  15, p. 337; 1927. A. E. Weber, Ann. der Phys.,  45, p. 801; 1914.

C. E. Weinland, this journal,  15, p. 337, 1927; this journal,  16, p. 295; 1928. E. A. Baker, Proc. Opt. Conv., part  1, p. 238; 1926. Weber, Ann. der Phys.,  45, p. 801; 1914.

C. E. Weinland, this journal,  15, p. 337; 1927.

L. S. Ornstein and M. Minnaert, ZS. für Phys.,  43, p. 404; 1927.

T. R. Merton, Proc. Roy. Soc.,  113, p. 697, 1927; ibid., 106, p. 378, 1924.
[Crossref]

A. L. Schoen, this journal,  14, p. 179; 1927.

1926 (6)

R. J. Lang and S. Smith, this journal,  12, p. 523; 1926.

M. L. Dundon, A. L. Schoen, and R. M. Briggs, this journal,  12, p. 397; 1926. Spectroscopy, E.C.C. Baly, Longmans, 2, p. 357; 1927. H. Babcock, Amer. Phys. Soc. meeting, Berkeley, June 1929.
[Crossref]

H. F. Kurtz, this journal,  13, p. 495; 1926.
[Crossref]

R. Frerichs, Ann. der Phys.,  386, p. 813; 1926.

K. S. Gibson, this journal,  13, p. 267; 1926. T. M. Dahm, this journal,  15, p. 266; 1927. L. A. Jones, this journal,  16, p. 259; 1928.
[Crossref]

L. A. Jones and O. Sandvik, this journal,  12; p. 401; 1926. P. Lafay, Rev. d’Optique,  7, p. 495; 1928.

1925 (15)

W. H. J. Moll and H. C. Burger, Phil. Mag.,  50, p. 624, 1925. ZS. für Phys.,  34, p. 109. 1925. J. Taylor, The Wireless Eng., p. 627; Oct.1927.
[Crossref]

L. S. Ornstein, Proc. Phys. Soc. Lond,  37; p. 334, 1925. Phys. ZS. 28, p. 688, 1927.

H. B. Dorgelo. Phys. ZS.,  26, p. 756; 1925.

G. R. Harrison, this journal,  11, p. 341; 1925.

G. R. Harrison and G. S. Forbes, this journal,  10, p. 1; 1925. Forbes and Harrison, this journal,  11, p. 99; 1925. D. C. Stockbarger, this journal,  14, p. 356; 1927.

L. S. Ornstein, Proc. Phys. Soc. Lond.,  37, p. 337; 1925.
[Crossref]

H. B. Dorgelo, Phys. ZS.,  26, p. 767; 1925.

W. E. Forsythe, this journal,  10, p. 19, 1925; this journal,  5, p. 494; 1921. C. O. Fairchild and W. E. Hoover, this journal,  7, p. 542; 1923.

Ibid.G. R. Harrison, this journal,  11, p. 113; 1925.

L. A. Jones, this journal,  10, p. 561, 1925; Bull. N.R.C.,  61, p. 109; 1927.
[Crossref]

W. Clark, Phot. Jour.,  65, p. 76; 1925.

G. R. Harrison, this journal,  10, p. 157; 1925.

G. Hansen, Ann. der Phys.,  383, p. 558; 1925R. Frerichs, Ann. der Phys.,  386 p. 809; 1925.
[Crossref]

J. A. Parkhurst and A. H. Farnsworth, Astrophys. Jour.,  62, p. 179; 1925. C. Davidson, J.S.I.,  5, p. 238; 1928.

H. B. Dorgelo, Phys. ZS.,  26, p. 790; 1925.

1924 (4)

J. S. Foster, this journal,  8, p. 373; 1924 Nicholson and Merton, Phil. Trans.,  216, p. 459; 1916. I. O. Griffith, Proc. Phys. Soc. Lond.,  38, p. 85; 1925.

T. R. Merton, Proc. Roy. Soc., 1924.
[Crossref]

T. R. Merton, Proc. Roy. Soc.,  106, p. 378; 1924.

G. R. Harrison, Phys. Rev.,  24, p. 477, 1924; Phys. Rev.,  25, p. 768, 1925. Harrison and C. E. Hesthal, this journal,  8, p. 471; 1924.

1923 (7)

E. T. Bovie, this journal,  7, p. 1026; 1923.
[Crossref]

P. H. van Cittert, Physica,  3, p. 182, 1923; Rev. d’Opt.,  2, p. 57, 1923. (or see Ornstein, ref. 4, p. 340, or Dorgelo, ref. 5, p. 771.)

G. R. Harrison, this journal,  7, p. 999; 1923.

A. L. Schoen, this journal,  7, p. 483; 1923. C. B. Bazzoni, R. W. Duncan, and W. S. Mathews, this journal,  7, p. 1003; 1923. F. C. Toy, Proc. Phys. Soc. Lond.,  36, p. 432; 1924. Toy and Rawling, Jour. Sci. Inst. 1, p. 362; 1924. J. Kaplan, this journal,  14, p. 251, 1927 (use of thalofide cell).

G. M. B. Dobson, Proc. Roy. Soc.,  104, p. 248; 1923.
[Crossref]

L. A. Jones, this journal,  7, p. 231; 1923.

L. A. Jones, this journal,  7, p. 231; 1923.
[Crossref]

1922 (2)

T. Lyman, Nature,  112, p. 202; 1922.
[Crossref]

A. H. Pfund, Jour. Frank. Inst.,  192, p. 641; 1922. E. Karrer, this journal,  7, p. 893; 1923.
[Crossref]

1921 (2)

J. Brentano, Nature, Dec.22, 1921; Phil. Mag. 7, 685; 1929. Rosenberg, ZS. für Phys.,  7, p. 18; 1921. C. E. Wynn-Williams, Phil. Mag.,  6, p. 324, 1928; Proc. Camb. Phil. Soc.,  23, p. 811, 1927. A. Marcus, Phys. Rev.,  31, p. 302; 1928. J. Razek and P. J. Mulder, P. Rev.,  33, p. 284; 1929.
[Crossref]

Duclaux and Jeantet, Jour. de Phys. et Le Rad.,  2, p. 154; 1921.

1920 (4)

G. Gelhoff, ZS. für Techn. Phys.,  1, p. 224; 1920. J. Franck and W. Grotrian, ZS. für Techn. Phys.,  3, p. 195; 1922. D. C. Stockbarger, this journal,  9, p. 237; 1924.

F. Bates, Phil. Mag.,  39, p. 353, 1920; Bull. Bur. Stds.,  16, p. 45; 1920.

F. E. Ross, this journal,  4, p. 255; 1920. P. S. Helmick, this journal,  5, p. 336; 1921.

F. E. Ross, Astrophys. Jour.,  52; p. 86; 1920.
[Crossref]

1919 (1)

S. J. Lewis, Jour. Chem. Soc. Trans.,  115, p. 312; 1919.

1917 (2)

T. R. Merton and J. W. Nicholson, Phil. Trans. 217, p. 237; 1917. Merton, ref. 61.

A. E. Worthing, Phys. Rev.,  10, p. 377; 1917. Hyde, Cady, and Forsythe, Jour. Frank. Inst.,  181, p. 418; 1916. Int. Crit. Tables, 5, pp. 245–246.
[Crossref]

1916 (1)

H. T. Stetson, Astrophys. Jour.,  43. pp. 253 and 325; 1916. W. H. J. Moll, Proc. Phys. Soc. Lond.,  33, p. 207; 1921. Stetson and Carpenter, Astrophys. Jour.,  58, p. 36; 1923. E. Pettit and S. B. Nicholson, this journal,  7, p. 187; 1923. M. Siegbahn, Phil. Mag.,  48, p. 217; 1924. G. R. Harrison, loc. cit., 1925. E. Backlin, ZS. für Inst.,  47, p. 373; 1927. E. Spiller, ZS. für. Inst.,  47, p. 493; 1927. E. A. Harrington, this journal,  16, p. 211; 1928.
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1914 (2)

H. Ewest, Beitrage zur Quantitativen Spectralphotographie. Abstract in English by F. F. Renwick, Phot. Jour.,  54, p. 99; 1914. Slade and Toy, Proc. Roy. Soc.,  97, p. 181; 1920. T. R. Merton, Proc. Roy. Soc.,  99, p. 78; 1921. A. L. Narayan, Phil. Mag.,  43, p. 662; 1922. H. H. Plaskett, Dom Ast. Obs. Pub.,  2, p. 213; 1923. R. Frerichs, ZS. für Phys.,  35, p. 524; 1926. H. M. Kellner, ZS. Wiss. Phot.,  24, p. 41; 1926. C. Fabry, Phot. Jour.,  66, p. 328; 1926. H. Ley and F. Volbert, ZS. Phys. Chem.,  130, p. 308; 1927. H. v. Alband and J. Eisenbrand, Proc. Roy. Soc.,  116, p. 153, 1927; ZS. Wiss Phot.,  25, p. 138, 1928. C. H. Payne and F. S. Hogg, Proc. Nat. Acad. Sci.,  14, p. 88; 1928. L. Lobel and J. Lefevre, Rev. d’Opt.,  6, p. 377; 1927. J. K. Robertson, this journal,  7, p. 983; 1923. K. Schachtschabel, Ann. der Phys.,  81, 929; 1926. I. Wynekin, Ann. der Phys.,  86, p. 1071; 1928. Baly, Morton, and Rinding, Proc. Roy. Soc.,  113, p. 709; 1927. K. Schaum, ZS. Wiss. Phot.,  22, p. 148; 1923.

H. Ewest, Beitrage zur Quantitativen Spectralphotographie. Abstract in English by F. F. Renwick, Phot. Jour.,  54, p. 99; 1914. Slade and Toy, Proc. Roy. Soc.,  97, p. 181; 1920. T. R. Merton, Proc. Roy. Soc.,  99, p. 78; 1921. A. L. Narayan, Phil. Mag.,  43, p. 662; 1922. H. H. Plaskett, Dom Ast. Obs. Pub.,  2, p. 213; 1923. R. Frerichs, ZS. für Phys.,  35, p. 524; 1926. H. M. Kellner, ZS. Wiss. Phot.,  24, p. 41; 1926. C. Fabry, Phot. Jour.,  66, p. 328; 1926. H. Ley and F. Volbert, ZS. Phys. Chem.,  130, p. 308; 1927. H. v. Alband and J. Eisenbrand, Proc. Roy. Soc.,  116, p. 153, 1927; ZS. Wiss Phot.,  25, p. 138, 1928. C. H. Payne and F. S. Hogg, Proc. Nat. Acad. Sci.,  14, p. 88; 1928. L. Lobel and J. Lefevre, Rev. d’Opt.,  6, p. 377; 1927. J. K. Robertson, this journal,  7, p. 983; 1923. K. Schachtschabel, Ann. der Phys.,  81, 929; 1926. I. Wynekin, Ann. der Phys.,  86, p. 1071; 1928. Baly, Morton, and Rinding, Proc. Roy. Soc.,  113, p. 709; 1927. K. Schaum, ZS. Wiss. Phot.,  22, p. 148; 1923.

Ham, Fehr, and Bitner, Jour. Frank. Inst.,  178, p. 299; 1914.
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1912 (2)

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912. Koch and A. S. King, Astrophys. Jour.,  39, p. 213; 1914. F. Goos, ZS. für Inst.,  41, p. 313, 1921; Phys. ZS.,  22, p. 468; 1921. J. O. Perrine, this journal,  8, p. 381; 1924. L. F. Behr, Boston Meeting Opt. Soc. Amer., Oct. 1924. E. A. Baker, Jour. Sci. Inst., p. 345, 1924; Proc. Roy. Soc. Edin., 45, pt. 2. P. P. Koch, ZS. für Inst.,  45, p. 294; 1925. F. A. Lindemann and G. M. B. Dobson, Engineering,  122, p. 403; 1926. E. Banty, Rev. d’Opt.,  5, p. 404; 1926. F. Goos and P. P. Koch, Phys. ZS.,  27, p. 41; 1926. F. Goos and P. P. Koch, ZS. für Phys.,  44, p. 855; 1927. Goldschmidt, Meteorolog. ZS., p. 241; 1926. F. C. Toy, Jour. Sci. Inst.,  4, p. 369; 1927. Muller, ZS. f. Techn. Phys., p. 154; 1928.

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912.

1910 (2)

C. F. Brush, Brit. Jour. Phot.,  57, p. 781, 1910; Phys. Rev.,  31, p. 241, 1910.
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A. Eagle, Astrophys. Jour.,  31, p. 120; 1910.
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1908 (1)

W. W. Coblentz, Bull. Bur. Stds.,  4, p. 392, 1908; Bull. Bur. Stds.,  9, p. 7, 1911; Bull. Bur. Stds.,  11, p. 132, 1914; Bull. Bur. Stds.,  12, p. 504, 1916; this journal,  7, p. 439, 1923; this journal,  5, p. 259, 1921. W. H. J. Moll and H. C. Burger, Phil Mag.,  50, p. 618, 1925; Phil Mag.,  50, p. 626, 1925. ZS. für Phys.,  34; p. 112, 1925; Rev. d’Opt.,  4, p. 562, 1925.
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1901 (1)

V. Schumann, Ann. der Phys.,  5, p. 349; 1901.
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1900 (1)

K. Schwarzschild, Astrophys. Jour.,  11, p. 89; 1900.
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1895 (1)

F. Wadsworth, Astrophys. Jour.,  2, 370; 1895. W. F. Meggers, .
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Abe, T.

T. Abe, Mazda Kenkyu-Jiho,  3, p. 325; 1928. (In English.)

Abney, W. de W.

W. de W. Abney, Phot. Jour.,  18, p. 302; 1893–4. L. A. Jones and E. Huse, this journal, 7, p. 1079–4. L. A. Jones and E. Huse, this journal, 7, p. 1923 (refs.). L. A. Jones, V. C. Hall, and R. M. Briggs, this journal,  14, p. 223; 1927 (refs.).

Alphen, H. C. v.

H. C. v. Alphen, Ann. der Phys.,  85, p. 1058; 1928.

Anderson, W. T.

W. T. Anderson, H. D. Frazer, and L. F. Bird, this journal,  17, p. 454; 1928.

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E. A. Baker, loc. cit.
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Baly, E. C. C.

E. C. C. Baly, Spectroscopy, 2, p. 380.

Bates, F.

F. Bates, Phil. Mag.,  39, p. 353, 1920; Bull. Bur. Stds.,  16, p. 45; 1920.

Bird, L. F.

W. T. Anderson, H. D. Frazer, and L. F. Bird, this journal,  17, p. 454; 1928.

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Ham, Fehr, and Bitner, Jour. Frank. Inst.,  178, p. 299; 1914.
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Bloch, O.

O. Bloch and H. Horton, Phot. Jour.,  68, p. 352; 1928.

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E. T. Bovie, this journal,  7, p. 1026; 1923.
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Brentano, J.

J. Brentano, Nature, Dec.22, 1921; Phil. Mag. 7, 685; 1929. Rosenberg, ZS. für Phys.,  7, p. 18; 1921. C. E. Wynn-Williams, Phil. Mag.,  6, p. 324, 1928; Proc. Camb. Phil. Soc.,  23, p. 811, 1927. A. Marcus, Phys. Rev.,  31, p. 302; 1928. J. Razek and P. J. Mulder, P. Rev.,  33, p. 284; 1929.
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Briggs, R. M.

M. L. Dundon, A. L. Schoen, and R. M. Briggs, this journal,  12, p. 397; 1926. Spectroscopy, E.C.C. Baly, Longmans, 2, p. 357; 1927. H. Babcock, Amer. Phys. Soc. meeting, Berkeley, June 1929.
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Brush, C. F.

C. F. Brush, Brit. Jour. Phot.,  57, p. 781, 1910; Phys. Rev.,  31, p. 241, 1910.
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Burger, H. C.

W. H. J. Moll and H. C. Burger, Phil. Mag.,  50, p. 624, 1925. ZS. für Phys.,  34, p. 109. 1925. J. Taylor, The Wireless Eng., p. 627; Oct.1927.
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Clark, W.

W. Clark, Phot. Jour.,  65, p. 76; 1925.

Coblentz, W. W.

W. W. Coblentz, Bull. Bur. Stds.,  4, p. 392, 1908; Bull. Bur. Stds.,  9, p. 7, 1911; Bull. Bur. Stds.,  11, p. 132, 1914; Bull. Bur. Stds.,  12, p. 504, 1916; this journal,  7, p. 439, 1923; this journal,  5, p. 259, 1921. W. H. J. Moll and H. C. Burger, Phil Mag.,  50, p. 618, 1925; Phil Mag.,  50, p. 626, 1925. ZS. für Phys.,  34; p. 112, 1925; Rev. d’Opt.,  4, p. 562, 1925.
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Ditchburn, R. W.

R. W. Ditchburn, Camb. Phil. Soc. Proc.,  23, p. 959; 1927.

Dobson, G. M. B.

G. M. B. Dobson, Proc. Roy. Soc.,  104, p. 248; 1923.
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Photographic Photometry, by G. M. B. Dobson, I. O. Griffith, and D. N. Harrison, Oxford, University Press, p. 121; 1926.

Dorgelo,

Dorgelo, ref. 5, p. 771.

Dorgelo, H. B.

H. B. Dorgelo, Phys. ZS.,  26, p. 767; 1925.

H. B. Dorgelo. Phys. ZS.,  26, p. 756; 1925.

H. B. Dorgelo, Phys. ZS.,  26, p. 790; 1925.

H. B. Dorgelo, Diss. Utrecht, 1924. R. Frerichs, ZS. f. Phys.,  31, p. 305; 1925.

Duclaux,

Duclaux and Jeantet, Jour. de Phys. et Le Rad.,  2, p. 154; 1921.

Dundon, M. L.

M. L. Dundon, A. L. Schoen, and R. M. Briggs, this journal,  12, p. 397; 1926. Spectroscopy, E.C.C. Baly, Longmans, 2, p. 357; 1927. H. Babcock, Amer. Phys. Soc. meeting, Berkeley, June 1929.
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Eagle, A.

A. Eagle, Astrophys. Jour.,  31, p. 120; 1910.
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Engwicht, H.

G. R. Harrison and H. Engwicht, this journal,  18, p. 287; 1929. (See also refs. 17, 18, 20, and 38.)

Ewest, H.

H. Ewest, Beitrage zur Quantitativen Spectralphotographie. Abstract in English by F. F. Renwick, Phot. Jour.,  54, p. 99; 1914. Slade and Toy, Proc. Roy. Soc.,  97, p. 181; 1920. T. R. Merton, Proc. Roy. Soc.,  99, p. 78; 1921. A. L. Narayan, Phil. Mag.,  43, p. 662; 1922. H. H. Plaskett, Dom Ast. Obs. Pub.,  2, p. 213; 1923. R. Frerichs, ZS. für Phys.,  35, p. 524; 1926. H. M. Kellner, ZS. Wiss. Phot.,  24, p. 41; 1926. C. Fabry, Phot. Jour.,  66, p. 328; 1926. H. Ley and F. Volbert, ZS. Phys. Chem.,  130, p. 308; 1927. H. v. Alband and J. Eisenbrand, Proc. Roy. Soc.,  116, p. 153, 1927; ZS. Wiss Phot.,  25, p. 138, 1928. C. H. Payne and F. S. Hogg, Proc. Nat. Acad. Sci.,  14, p. 88; 1928. L. Lobel and J. Lefevre, Rev. d’Opt.,  6, p. 377; 1927. J. K. Robertson, this journal,  7, p. 983; 1923. K. Schachtschabel, Ann. der Phys.,  81, 929; 1926. I. Wynekin, Ann. der Phys.,  86, p. 1071; 1928. Baly, Morton, and Rinding, Proc. Roy. Soc.,  113, p. 709; 1927. K. Schaum, ZS. Wiss. Phot.,  22, p. 148; 1923.

Farnsworth, A. H.

J. A. Parkhurst and A. H. Farnsworth, Astrophys. Jour.,  62, p. 179; 1925. C. Davidson, J.S.I.,  5, p. 238; 1928.

Fehr,

Ham, Fehr, and Bitner, Jour. Frank. Inst.,  178, p. 299; 1914.
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Forbes, G. S.

G. R. Harrison and G. S. Forbes, this journal,  10, p. 1; 1925. Forbes and Harrison, this journal,  11, p. 99; 1925. D. C. Stockbarger, this journal,  14, p. 356; 1927.

Forsythe, W. E.

W. E. Forsythe, this journal,  16, p. 307; 1928.

W. E. Forsythe, this journal,  10, p. 19, 1925; this journal,  5, p. 494; 1921. C. O. Fairchild and W. E. Hoover, this journal,  7, p. 542; 1923.

Foster, J. S.

J. S. Foster, this journal,  8, p. 373; 1924 Nicholson and Merton, Phil. Trans.,  216, p. 459; 1916. I. O. Griffith, Proc. Phys. Soc. Lond.,  38, p. 85; 1925.

Frazer, H. D.

W. T. Anderson, H. D. Frazer, and L. F. Bird, this journal,  17, p. 454; 1928.

Frerichs, R.

R. Frerichs, Ann. der Phys.,  386, p. 813; 1926.

Gelhoff, G.

G. Gelhoff, ZS. für Techn. Phys.,  1, p. 224; 1920. J. Franck and W. Grotrian, ZS. für Techn. Phys.,  3, p. 195; 1922. D. C. Stockbarger, this journal,  9, p. 237; 1924.

Gibson, K. S.

K. S. Gibson, this journal,  13, p. 267; 1926. T. M. Dahm, this journal,  15, p. 266; 1927. L. A. Jones, this journal,  16, p. 259; 1928.
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Griffith, I. O.

Photographic Photometry, by G. M. B. Dobson, I. O. Griffith, and D. N. Harrison, Oxford, University Press, p. 121; 1926.

Ham,

Ham, Fehr, and Bitner, Jour. Frank. Inst.,  178, p. 299; 1914.
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Hansen, G.

G. Hansen, Ann. der Phys.,  383, p. 558; 1925R. Frerichs, Ann. der Phys.,  386 p. 809; 1925.
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Hardy, A. C.

See A. C. Hardy, this journal,  18, p. 96; 1929. K. S. Gibson, this journal,  7, p. 693; 1923.

Harrison, D. N.

Photographic Photometry, by G. M. B. Dobson, I. O. Griffith, and D. N. Harrison, Oxford, University Press, p. 121; 1926.

Harrison, G. R.

G. R. Harrison, this journal,  18, p. 492; 1929.
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G. R. Harrison and H. Engwicht, this journal,  18, p. 287; 1929. (See also refs. 17, 18, 20, and 38.)

G. R. Harrison, this journal,  16, p. 63; 1928.
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G. R. Harrison, this journal,  17, p. 389; 1928.

G. R. Harrison and G. S. Forbes, this journal,  10, p. 1; 1925. Forbes and Harrison, this journal,  11, p. 99; 1925. D. C. Stockbarger, this journal,  14, p. 356; 1927.

G. R. Harrison, this journal,  11, p. 341; 1925.

G. R. Harrison, this journal,  10, p. 157; 1925.

Ibid.G. R. Harrison, this journal,  11, p. 113; 1925.

G. R. Harrison, Phys. Rev.,  24, p. 477, 1924; Phys. Rev.,  25, p. 768, 1925. Harrison and C. E. Hesthal, this journal,  8, p. 471; 1924.

G. R. Harrison, this journal,  7, p. 999; 1923.

G. R. Harrison, this journal, in press.
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C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June 1929, Abst. 16.

Henri, V.

Catalogs of Adam Hilger, Ltd.V. Henri, Etudes de Photochimie, Paris, Gauthier-Villars, 1919. H. E. Howe, Phys. Rev.,  8, p. 674; 1916. H. J. McNicholas, Bur. Stds. Jour. Res.,  1, p. 939; 1928. ; 18, p. 121; 1922. V. Hardung, Helv. Phys. Acta,  1, p. 472; 1928. Proc. Roy. Soc. Lond,  120, p. 21; 1928.
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Hesthal, C. E.

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June 1929, Abst. 16.

Horton, H.

O. Bloch and H. Horton, Phot. Jour.,  68, p. 352; 1928.

Huse, E.

L. A. Jones and E. Huse, loc cit.

Jeantet,

Duclaux and Jeantet, Jour. de Phys. et Le Rad.,  2, p. 154; 1921.

Jones, L. A.

L. A. Jones and O. Sandvik, this journal,  12; p. 401; 1926. P. Lafay, Rev. d’Optique,  7, p. 495; 1928.

L. A. Jones, this journal,  10, p. 561, 1925; Bull. N.R.C.,  61, p. 109; 1927.
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L. A. Jones, this journal,  7, p. 231; 1923.
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L. A. Jones, this journal,  7, p. 231; 1923.

L. A. Jones and E. Huse, loc cit.

Koch, P. P.

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912. Koch and A. S. King, Astrophys. Jour.,  39, p. 213; 1914. F. Goos, ZS. für Inst.,  41, p. 313, 1921; Phys. ZS.,  22, p. 468; 1921. J. O. Perrine, this journal,  8, p. 381; 1924. L. F. Behr, Boston Meeting Opt. Soc. Amer., Oct. 1924. E. A. Baker, Jour. Sci. Inst., p. 345, 1924; Proc. Roy. Soc. Edin., 45, pt. 2. P. P. Koch, ZS. für Inst.,  45, p. 294; 1925. F. A. Lindemann and G. M. B. Dobson, Engineering,  122, p. 403; 1926. E. Banty, Rev. d’Opt.,  5, p. 404; 1926. F. Goos and P. P. Koch, Phys. ZS.,  27, p. 41; 1926. F. Goos and P. P. Koch, ZS. für Phys.,  44, p. 855; 1927. Goldschmidt, Meteorolog. ZS., p. 241; 1926. F. C. Toy, Jour. Sci. Inst.,  4, p. 369; 1927. Muller, ZS. f. Techn. Phys., p. 154; 1928.

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912.

Kurtz, H. F.

H. F. Kurtz, this journal,  13, p. 495; 1926.
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Lang, R. J.

R. J. Lang and S. Smith, this journal,  12, p. 523; 1926.

Lewis, S. J.

S. J. Lewis, Jour. Chem. Soc. Trans.,  115, p. 312; 1919.

Lyman, T.

T. Lyman, Nature,  112, p. 202; 1922.
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T. Lyman, Spectroscopy of the Extreme Ultraviolet. P. R. Gleason, Proc. Nat. Acad. Soc.,  15, p. 551; 1929.
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Mees, C. E. K.

See Investigations on the Theory of the Photographic Process, S. E. Sheppard and C. E. K. Mees, Longmans, 1907.

Merton, T. R.

T. R. Merton, Proc. Roy. Soc.,  113, p. 697, 1927; ibid., 106, p. 378, 1924.
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T. R. Merton, Proc. Roy. Soc., 1924.
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T. R. Merton, Proc. Roy. Soc.,  106, p. 378; 1924.

T. R. Merton and J. W. Nicholson, Phil. Trans. 217, p. 237; 1917. Merton, ref. 61.

Minnaert, M.

L. S. Ornstein and M. Minnaert, ZS. für Phys.,  43, p. 404; 1927.

L. S. Ornstein and M. Minnaert, ZS. fur Phys.,  43, p. 404; 1927.

Moll, W. H. J.

W. H. J. Moll and H. C. Burger, Phil. Mag.,  50, p. 624, 1925. ZS. für Phys.,  34, p. 109. 1925. J. Taylor, The Wireless Eng., p. 627; Oct.1927.
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Nicholson, J. W.

T. R. Merton and J. W. Nicholson, Phil. Trans. 217, p. 237; 1917. Merton, ref. 61.

Nicholson, S. B.

E. Pettit and S. B. Nicholson, loc. cit.

Olpin, A. R.

A. R. Olpin, Amer. Phys. Soc. Proc., Washington meeting, Apr. 1929, Abst. 57. Berkeley Meeting, June 1929, Abst. 17.
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Ornstein, L. S.

L. S. Ornstein and M. Minnaert, ZS. fur Phys.,  43, p. 404; 1927.

L. S. Ornstein and M. Minnaert, ZS. für Phys.,  43, p. 404; 1927.

L. S. Ornstein, Proc. Phys. Soc. Lond,  37; p. 334, 1925. Phys. ZS. 28, p. 688, 1927.

L. S. Ornstein, Proc. Phys. Soc. Lond.,  37, p. 337; 1925.
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Parkhurst, J. A.

J. A. Parkhurst and A. H. Farnsworth, Astrophys. Jour.,  62, p. 179; 1925. C. Davidson, J.S.I.,  5, p. 238; 1928.

Pettit, E.

E. Pettit and S. B. Nicholson, loc. cit.

Pfund, A. H.

A. H. Pfund, Jour. Frank. Inst.,  192, p. 641; 1922. E. Karrer, this journal,  7, p. 893; 1923.
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Renwick, F. F.

H. Ewest, Beitrage zur Quantitativen Spectralphotographie. Abstract in English by F. F. Renwick, Phot. Jour.,  54, p. 99; 1914. Slade and Toy, Proc. Roy. Soc.,  97, p. 181; 1920. T. R. Merton, Proc. Roy. Soc.,  99, p. 78; 1921. A. L. Narayan, Phil. Mag.,  43, p. 662; 1922. H. H. Plaskett, Dom Ast. Obs. Pub.,  2, p. 213; 1923. R. Frerichs, ZS. für Phys.,  35, p. 524; 1926. H. M. Kellner, ZS. Wiss. Phot.,  24, p. 41; 1926. C. Fabry, Phot. Jour.,  66, p. 328; 1926. H. Ley and F. Volbert, ZS. Phys. Chem.,  130, p. 308; 1927. H. v. Alband and J. Eisenbrand, Proc. Roy. Soc.,  116, p. 153, 1927; ZS. Wiss Phot.,  25, p. 138, 1928. C. H. Payne and F. S. Hogg, Proc. Nat. Acad. Sci.,  14, p. 88; 1928. L. Lobel and J. Lefevre, Rev. d’Opt.,  6, p. 377; 1927. J. K. Robertson, this journal,  7, p. 983; 1923. K. Schachtschabel, Ann. der Phys.,  81, 929; 1926. I. Wynekin, Ann. der Phys.,  86, p. 1071; 1928. Baly, Morton, and Rinding, Proc. Roy. Soc.,  113, p. 709; 1927. K. Schaum, ZS. Wiss. Phot.,  22, p. 148; 1923.

Ross, F. E.

F. E. Ross, this journal,  4, p. 255; 1920. P. S. Helmick, this journal,  5, p. 336; 1921.

F. E. Ross, Astrophys. Jour.,  52; p. 86; 1920.
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Sandvik, O.

L. A. Jones and O. Sandvik, this journal,  12; p. 401; 1926. P. Lafay, Rev. d’Optique,  7, p. 495; 1928.

Schoen, A. L.

A. L. Schoen, this journal,  14, p. 179; 1927.

M. L. Dundon, A. L. Schoen, and R. M. Briggs, this journal,  12, p. 397; 1926. Spectroscopy, E.C.C. Baly, Longmans, 2, p. 357; 1927. H. Babcock, Amer. Phys. Soc. meeting, Berkeley, June 1929.
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A. L. Schoen, this journal,  7, p. 483; 1923. C. B. Bazzoni, R. W. Duncan, and W. S. Mathews, this journal,  7, p. 1003; 1923. F. C. Toy, Proc. Phys. Soc. Lond.,  36, p. 432; 1924. Toy and Rawling, Jour. Sci. Inst. 1, p. 362; 1924. J. Kaplan, this journal,  14, p. 251, 1927 (use of thalofide cell).

Schumann, V.

V. Schumann, Ann. der Phys.,  5, p. 349; 1901.
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Schwarzschild, K.

K. Schwarzschild, Astrophys. Jour.,  11, p. 89; 1900.
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Sheppard, S. E.

See Investigations on the Theory of the Photographic Process, S. E. Sheppard and C. E. K. Mees, Longmans, 1907.

Smith, S.

R. J. Lang and S. Smith, this journal,  12, p. 523; 1926.

Snith, T. T.

T. T. Snith, this journal,  17, p. 145; 1928.
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Stetson, H. T.

H. T. Stetson, Astrophys. Jour.,  43. pp. 253 and 325; 1916. W. H. J. Moll, Proc. Phys. Soc. Lond.,  33, p. 207; 1921. Stetson and Carpenter, Astrophys. Jour.,  58, p. 36; 1923. E. Pettit and S. B. Nicholson, this journal,  7, p. 187; 1923. M. Siegbahn, Phil. Mag.,  48, p. 217; 1924. G. R. Harrison, loc. cit., 1925. E. Backlin, ZS. für Inst.,  47, p. 373; 1927. E. Spiller, ZS. für. Inst.,  47, p. 493; 1927. E. A. Harrington, this journal,  16, p. 211; 1928.
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van Cittert, P. H.

P. H. van Cittert, Physica,  3, p. 182, 1923; Rev. d’Opt.,  2, p. 57, 1923. (or see Ornstein, ref. 4, p. 340, or Dorgelo, ref. 5, p. 771.)

Wadsworth, F.

F. Wadsworth, Astrophys. Jour.,  2, 370; 1895. W. F. Meggers, .
[Crossref]

Webster, H. C.

H. C. Webster, Proc. Phys. Soc. Lond.,  41, p. 181; 1929. H. T. Meyer, Wissenschaftliche Veröffentlichung aus dem Siemans-Konzern, 7te Band, 2 Heft, p. 109. A. Bowers, ZS. für Phys.,  14, p. 174, 1923; Physica,  3, p. 113, 1923; ibid., 5, p. 8, 1925. Diss. Utrecht1924. R. Glocker and W. Traub, Phys. ZS. 22, p. 345; 1921.

Weinland, C. E.

C. E. Weinland, this journal,  15, p. 337, 1927; this journal,  16, p. 295; 1928. E. A. Baker, Proc. Opt. Conv., part  1, p. 238; 1926. Weber, Ann. der Phys.,  45, p. 801; 1914.

C. E. Weinland, this journal,  15, p. 337; 1927.

C. E. Weinland, this journal,  15, p. 337; 1927 (refs.).

Wienland, C. E.

C. E. Wienland, this journal,  15, p. 337; 1927. A. E. Weber, Ann. der Phys.,  45, p. 801; 1914.

Wilsey, R. B.

R. B. Wilsey, Eastman Kodak Res. Lab. Comm. No. 239. R. B. Wilsey and H. A. Pritchard, this journal,  12, p. 661; 1926.
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Wood, R. W.

I. C. T.5, p. 335. R. W. Wood, Physical Optics, MacMillan.

Worthing, A. E.

A. E. Worthing, Phys. Rev.,  10, p. 377; 1917. Hyde, Cady, and Forsythe, Jour. Frank. Inst.,  181, p. 418; 1916. Int. Crit. Tables, 5, pp. 245–246.
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Zwikker, C.

C. Zwikker, Diss. Amsterdam1925. ( Dorgelo, Phys. ZS.,  26, p. 770; 1925.)

Ann. der Phys. (6)

R. Frerichs, Ann. der Phys.,  386, p. 813; 1926.

H. C. v. Alphen, Ann. der Phys.,  85, p. 1058; 1928.

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912. Koch and A. S. King, Astrophys. Jour.,  39, p. 213; 1914. F. Goos, ZS. für Inst.,  41, p. 313, 1921; Phys. ZS.,  22, p. 468; 1921. J. O. Perrine, this journal,  8, p. 381; 1924. L. F. Behr, Boston Meeting Opt. Soc. Amer., Oct. 1924. E. A. Baker, Jour. Sci. Inst., p. 345, 1924; Proc. Roy. Soc. Edin., 45, pt. 2. P. P. Koch, ZS. für Inst.,  45, p. 294; 1925. F. A. Lindemann and G. M. B. Dobson, Engineering,  122, p. 403; 1926. E. Banty, Rev. d’Opt.,  5, p. 404; 1926. F. Goos and P. P. Koch, Phys. ZS.,  27, p. 41; 1926. F. Goos and P. P. Koch, ZS. für Phys.,  44, p. 855; 1927. Goldschmidt, Meteorolog. ZS., p. 241; 1926. F. C. Toy, Jour. Sci. Inst.,  4, p. 369; 1927. Muller, ZS. f. Techn. Phys., p. 154; 1928.

P. P. Koch, Ann. der Phys.,  39, p. 705; 1912.

G. Hansen, Ann. der Phys.,  383, p. 558; 1925R. Frerichs, Ann. der Phys.,  386 p. 809; 1925.
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V. Schumann, Ann. der Phys.,  5, p. 349; 1901.
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Astrophys. Jour. (6)

J. A. Parkhurst and A. H. Farnsworth, Astrophys. Jour.,  62, p. 179; 1925. C. Davidson, J.S.I.,  5, p. 238; 1928.

H. T. Stetson, Astrophys. Jour.,  43. pp. 253 and 325; 1916. W. H. J. Moll, Proc. Phys. Soc. Lond.,  33, p. 207; 1921. Stetson and Carpenter, Astrophys. Jour.,  58, p. 36; 1923. E. Pettit and S. B. Nicholson, this journal,  7, p. 187; 1923. M. Siegbahn, Phil. Mag.,  48, p. 217; 1924. G. R. Harrison, loc. cit., 1925. E. Backlin, ZS. für Inst.,  47, p. 373; 1927. E. Spiller, ZS. für. Inst.,  47, p. 493; 1927. E. A. Harrington, this journal,  16, p. 211; 1928.
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F. E. Ross, Astrophys. Jour.,  52; p. 86; 1920.
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K. Schwarzschild, Astrophys. Jour.,  11, p. 89; 1900.
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A. Eagle, Astrophys. Jour.,  31, p. 120; 1910.
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F. Wadsworth, Astrophys. Jour.,  2, 370; 1895. W. F. Meggers, .
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Brit. Jour. Phot. (1)

C. F. Brush, Brit. Jour. Phot.,  57, p. 781, 1910; Phys. Rev.,  31, p. 241, 1910.
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Bull. Bur. Stds. (1)

W. W. Coblentz, Bull. Bur. Stds.,  4, p. 392, 1908; Bull. Bur. Stds.,  9, p. 7, 1911; Bull. Bur. Stds.,  11, p. 132, 1914; Bull. Bur. Stds.,  12, p. 504, 1916; this journal,  7, p. 439, 1923; this journal,  5, p. 259, 1921. W. H. J. Moll and H. C. Burger, Phil Mag.,  50, p. 618, 1925; Phil Mag.,  50, p. 626, 1925. ZS. für Phys.,  34; p. 112, 1925; Rev. d’Opt.,  4, p. 562, 1925.
[Crossref]

Camb. Phil. Soc. Proc. (1)

R. W. Ditchburn, Camb. Phil. Soc. Proc.,  23, p. 959; 1927.

Jour. Chem. Soc. Trans. (1)

S. J. Lewis, Jour. Chem. Soc. Trans.,  115, p. 312; 1919.

Jour. de Phys. et Le Rad. (1)

Duclaux and Jeantet, Jour. de Phys. et Le Rad.,  2, p. 154; 1921.

Jour. Frank. Inst. (2)

Ham, Fehr, and Bitner, Jour. Frank. Inst.,  178, p. 299; 1914.
[Crossref]

A. H. Pfund, Jour. Frank. Inst.,  192, p. 641; 1922. E. Karrer, this journal,  7, p. 893; 1923.
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Mazda Kenkyu-Jiho (1)

T. Abe, Mazda Kenkyu-Jiho,  3, p. 325; 1928. (In English.)

Nature (2)

T. Lyman, Nature,  112, p. 202; 1922.
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J. Brentano, Nature, Dec.22, 1921; Phil. Mag. 7, 685; 1929. Rosenberg, ZS. für Phys.,  7, p. 18; 1921. C. E. Wynn-Williams, Phil. Mag.,  6, p. 324, 1928; Proc. Camb. Phil. Soc.,  23, p. 811, 1927. A. Marcus, Phys. Rev.,  31, p. 302; 1928. J. Razek and P. J. Mulder, P. Rev.,  33, p. 284; 1929.
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Phil. Mag. (2)

F. Bates, Phil. Mag.,  39, p. 353, 1920; Bull. Bur. Stds.,  16, p. 45; 1920.

W. H. J. Moll and H. C. Burger, Phil. Mag.,  50, p. 624, 1925. ZS. für Phys.,  34, p. 109. 1925. J. Taylor, The Wireless Eng., p. 627; Oct.1927.
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Phil. Trans. (1)

T. R. Merton and J. W. Nicholson, Phil. Trans. 217, p. 237; 1917. Merton, ref. 61.

Phot. Jour. (3)

O. Bloch and H. Horton, Phot. Jour.,  68, p. 352; 1928.

W. Clark, Phot. Jour.,  65, p. 76; 1925.

W. de W. Abney, Phot. Jour.,  18, p. 302; 1893–4. L. A. Jones and E. Huse, this journal, 7, p. 1079–4. L. A. Jones and E. Huse, this journal, 7, p. 1923 (refs.). L. A. Jones, V. C. Hall, and R. M. Briggs, this journal,  14, p. 223; 1927 (refs.).

Phys. Rev. (2)

G. R. Harrison, Phys. Rev.,  24, p. 477, 1924; Phys. Rev.,  25, p. 768, 1925. Harrison and C. E. Hesthal, this journal,  8, p. 471; 1924.

A. E. Worthing, Phys. Rev.,  10, p. 377; 1917. Hyde, Cady, and Forsythe, Jour. Frank. Inst.,  181, p. 418; 1916. Int. Crit. Tables, 5, pp. 245–246.
[Crossref]

Phys. ZS. (3)

H. B. Dorgelo, Phys. ZS.,  26, p. 767; 1925.

H. B. Dorgelo. Phys. ZS.,  26, p. 756; 1925.

H. B. Dorgelo, Phys. ZS.,  26, p. 790; 1925.

Physica (1)

P. H. van Cittert, Physica,  3, p. 182, 1923; Rev. d’Opt.,  2, p. 57, 1923. (or see Ornstein, ref. 4, p. 340, or Dorgelo, ref. 5, p. 771.)

Proc. Phys. Soc. Lond (1)

L. S. Ornstein, Proc. Phys. Soc. Lond,  37; p. 334, 1925. Phys. ZS. 28, p. 688, 1927.

Proc. Phys. Soc. Lond. (2)

L. S. Ornstein, Proc. Phys. Soc. Lond.,  37, p. 337; 1925.
[Crossref]

H. C. Webster, Proc. Phys. Soc. Lond.,  41, p. 181; 1929. H. T. Meyer, Wissenschaftliche Veröffentlichung aus dem Siemans-Konzern, 7te Band, 2 Heft, p. 109. A. Bowers, ZS. für Phys.,  14, p. 174, 1923; Physica,  3, p. 113, 1923; ibid., 5, p. 8, 1925. Diss. Utrecht1924. R. Glocker and W. Traub, Phys. ZS. 22, p. 345; 1921.

Proc. Roy. Soc. (4)

T. R. Merton, Proc. Roy. Soc.,  106, p. 378; 1924.

T. R. Merton, Proc. Roy. Soc.,  113, p. 697, 1927; ibid., 106, p. 378, 1924.
[Crossref]

T. R. Merton, Proc. Roy. Soc., 1924.
[Crossref]

G. M. B. Dobson, Proc. Roy. Soc.,  104, p. 248; 1923.
[Crossref]

this journal (31)

T. T. Snith, this journal,  17, p. 145; 1928.
[Crossref]

A. L. Schoen, this journal,  7, p. 483; 1923. C. B. Bazzoni, R. W. Duncan, and W. S. Mathews, this journal,  7, p. 1003; 1923. F. C. Toy, Proc. Phys. Soc. Lond.,  36, p. 432; 1924. Toy and Rawling, Jour. Sci. Inst. 1, p. 362; 1924. J. Kaplan, this journal,  14, p. 251, 1927 (use of thalofide cell).

G. R. Harrison and H. Engwicht, this journal,  18, p. 287; 1929. (See also refs. 17, 18, 20, and 38.)

J. S. Foster, this journal,  8, p. 373; 1924 Nicholson and Merton, Phil. Trans.,  216, p. 459; 1916. I. O. Griffith, Proc. Phys. Soc. Lond.,  38, p. 85; 1925.

W. T. Anderson, H. D. Frazer, and L. F. Bird, this journal,  17, p. 454; 1928.

H. F. Kurtz, this journal,  13, p. 495; 1926.
[Crossref]

W. E. Forsythe, this journal,  16, p. 307; 1928.

C. E. Wienland, this journal,  15, p. 337; 1927. A. E. Weber, Ann. der Phys.,  45, p. 801; 1914.

L. A. Jones, this journal,  7, p. 231; 1923.

G. R. Harrison, this journal,  10, p. 157; 1925.

G. R. Harrison, this journal,  7, p. 999; 1923.

G. R. Harrison, this journal,  16, p. 63; 1928.
[Crossref]

K. S. Gibson, this journal,  13, p. 267; 1926. T. M. Dahm, this journal,  15, p. 266; 1927. L. A. Jones, this journal,  16, p. 259; 1928.
[Crossref]

G. R. Harrison, this journal,  18, p. 492; 1929.
[Crossref]

W. E. Forsythe, this journal,  10, p. 19, 1925; this journal,  5, p. 494; 1921. C. O. Fairchild and W. E. Hoover, this journal,  7, p. 542; 1923.

See A. C. Hardy, this journal,  18, p. 96; 1929. K. S. Gibson, this journal,  7, p. 693; 1923.

G. R. Harrison, this journal,  17, p. 389; 1928.

C. E. Weinland, this journal,  15, p. 337; 1927 (refs.).

G. R. Harrison and G. S. Forbes, this journal,  10, p. 1; 1925. Forbes and Harrison, this journal,  11, p. 99; 1925. D. C. Stockbarger, this journal,  14, p. 356; 1927.

E. T. Bovie, this journal,  7, p. 1026; 1923.
[Crossref]

F. E. Ross, this journal,  4, p. 255; 1920. P. S. Helmick, this journal,  5, p. 336; 1921.

G. R. Harrison, this journal,  11, p. 341; 1925.

L. A. Jones and O. Sandvik, this journal,  12; p. 401; 1926. P. Lafay, Rev. d’Optique,  7, p. 495; 1928.

L. A. Jones, this journal,  7, p. 231; 1923.
[Crossref]

C. E. Weinland, this journal,  15, p. 337, 1927; this journal,  16, p. 295; 1928. E. A. Baker, Proc. Opt. Conv., part  1, p. 238; 1926. Weber, Ann. der Phys.,  45, p. 801; 1914.

M. L. Dundon, A. L. Schoen, and R. M. Briggs, this journal,  12, p. 397; 1926. Spectroscopy, E.C.C. Baly, Longmans, 2, p. 357; 1927. H. Babcock, Amer. Phys. Soc. meeting, Berkeley, June 1929.
[Crossref]

A. L. Schoen, this journal,  14, p. 179; 1927.

Ibid.G. R. Harrison, this journal,  11, p. 113; 1925.

L. A. Jones, this journal,  10, p. 561, 1925; Bull. N.R.C.,  61, p. 109; 1927.
[Crossref]

C. E. Weinland, this journal,  15, p. 337; 1927.

R. J. Lang and S. Smith, this journal,  12, p. 523; 1926.

ZS. fur Phys. (1)

L. S. Ornstein and M. Minnaert, ZS. fur Phys.,  43, p. 404; 1927.

ZS. für Phys. (1)

L. S. Ornstein and M. Minnaert, ZS. für Phys.,  43, p. 404; 1927.

ZS. für Techn. Phys. (1)

G. Gelhoff, ZS. für Techn. Phys.,  1, p. 224; 1920. J. Franck and W. Grotrian, ZS. für Techn. Phys.,  3, p. 195; 1922. D. C. Stockbarger, this journal,  9, p. 237; 1924.

Other (19)

Dorgelo, ref. 5, p. 771.

E. Pettit and S. B. Nicholson, loc. cit.

C. E. Hesthal and G. R. Harrison, Bull. Amer. Phys. Soc., Berkeley Meeting, June 1929, Abst. 16.

E. A. Baker, loc. cit.
[Crossref]

A. R. Olpin, Amer. Phys. Soc. Proc., Washington meeting, Apr. 1929, Abst. 57. Berkeley Meeting, June 1929, Abst. 17.
[Crossref]

C. Zwikker, Diss. Amsterdam1925. ( Dorgelo, Phys. ZS.,  26, p. 770; 1925.)

H. B. Dorgelo, Diss. Utrecht, 1924. R. Frerichs, ZS. f. Phys.,  31, p. 305; 1925.

G. R. Harrison, this journal, in press.
[Crossref]

See Investigations on the Theory of the Photographic Process, S. E. Sheppard and C. E. K. Mees, Longmans, 1907.

Photographic Photometry, by G. M. B. Dobson, I. O. Griffith, and D. N. Harrison, Oxford, University Press, p. 121; 1926.

L. A. Jones and E. Huse, loc cit.

H. Ewest, Beitrage zur Quantitativen Spectralphotographie. Abstract in English by F. F. Renwick, Phot. Jour.,  54, p. 99; 1914. Slade and Toy, Proc. Roy. Soc.,  97, p. 181; 1920. T. R. Merton, Proc. Roy. Soc.,  99, p. 78; 1921. A. L. Narayan, Phil. Mag.,  43, p. 662; 1922. H. H. Plaskett, Dom Ast. Obs. Pub.,  2, p. 213; 1923. R. Frerichs, ZS. für Phys.,  35, p. 524; 1926. H. M. Kellner, ZS. Wiss. Phot.,  24, p. 41; 1926. C. Fabry, Phot. Jour.,  66, p. 328; 1926. H. Ley and F. Volbert, ZS. Phys. Chem.,  130, p. 308; 1927. H. v. Alband and J. Eisenbrand, Proc. Roy. Soc.,  116, p. 153, 1927; ZS. Wiss Phot.,  25, p. 138, 1928. C. H. Payne and F. S. Hogg, Proc. Nat. Acad. Sci.,  14, p. 88; 1928. L. Lobel and J. Lefevre, Rev. d’Opt.,  6, p. 377; 1927. J. K. Robertson, this journal,  7, p. 983; 1923. K. Schachtschabel, Ann. der Phys.,  81, 929; 1926. I. Wynekin, Ann. der Phys.,  86, p. 1071; 1928. Baly, Morton, and Rinding, Proc. Roy. Soc.,  113, p. 709; 1927. K. Schaum, ZS. Wiss. Phot.,  22, p. 148; 1923.

E. C. C. Baly, Spectroscopy, 2, p. 380.

Corning Glass Works, Catalog of Ultraviolet Glasses.

I. C. T.5, p. 335. R. W. Wood, Physical Optics, MacMillan.

T. Lyman, Spectroscopy of the Extreme Ultraviolet. P. R. Gleason, Proc. Nat. Acad. Soc.,  15, p. 551; 1929.
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.

Catalogs of Adam Hilger, Ltd.V. Henri, Etudes de Photochimie, Paris, Gauthier-Villars, 1919. H. E. Howe, Phys. Rev.,  8, p. 674; 1916. H. J. McNicholas, Bur. Stds. Jour. Res.,  1, p. 939; 1928. ; 18, p. 121; 1922. V. Hardung, Helv. Phys. Acta,  1, p. 472; 1928. Proc. Roy. Soc. Lond,  120, p. 21; 1928.
[Crossref]

R. B. Wilsey, Eastman Kodak Res. Lab. Comm. No. 239. R. B. Wilsey and H. A. Pritchard, this journal,  12, p. 661; 1926.
[Crossref]

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Figures (9)

Fig. 1
Fig. 1

Characteristic curves obtained with monochromatic light on typical emulsions of (a) low speed and high contrast, and (b) high speed and low contrast.

Fig. 2
Fig. 2

Graph in three dimensions showing a family of characteristic curves (d−log I) and a family of H. & D. curves (d−log t) for a typical emulsion. The contrast is 1.2, but from the d−log t curves the apparent contrast is only 0.66, making the value of Schwarzschild’s p 0.55. This factor is not quite constant, however. Large errors would result from calibrating such an emulsion by varying the time of exposure instead of the intensity unless the values of p were accurately determined, and this is not usually worth while.

Fig. 3
Fig. 3

The solid curve shows the variation of sensitivity (defined here as the reciprocal of the light intensity required to produce unit density in a given time) with wave length for an ordinary emulsion under conditions such as are frequently met with in photometry. The dotted line shows roughly the course of the sensitivity curve obtained by inspection of the usual wedge photographs showing the sensitivities of photographic materials. The difference between the two is due to the fact that the latter curve has not been corrected for the absorption by the glasss in the neutral wedge and in the lamp used in making the photograph, nor for the variation of light intensity with wave length.

Fig. 4
Fig. 4

Curves showing the variation of contrast with wave length for three typical emulsions, respectively slow, medium, and fast.

Fig. 5
Fig. 5

A portion of a spectrum plate obtained in making intensity measurements with a 10 meter concave grating in the second order, dispersion 0.79A/mm. (a) Spectra to be measured, (b) Exposures to a standard incandescent lamp at various temperatures, (c) Calibration exposures. The exposures (b) and (c) are taken through narrow slots in a diaphragm, and occur in sets 25A apart, taken simultaneously, the plate being moved sideways through about an inch during the taking of a number of sets of exposures. The lines in the exposures a in this particular specimen are too uneven to be of value for photometry. Five exposures of type a present on the original plate are not shown in the figure.

Fig. 6
Fig. 6

A convenient type of grating mounting for use in intensity work, suitable for gratings of any radius from one to ten meters or more.

Fig. 7
Fig. 7

A convenient black body furnace for use as an intensity distribution standard throughout the visible and into the ultraviolet as far as 2600A. Q, quartz window through which light from the slit S in the filament F emerges. A 10 kw transformer, terminal voltage 10 volts, sends a current of from 200 to 300 amperes from M to N. The top T is waxed to the base B with soft laboratory wax, and is exhausted to a few mm pressure through P. Some water vapor sweats through the brass jacket (which should preferably be made of copper) but this is largely taken up by the graphite cylinder G which gets red hot. The 1/4 inch filament F can be run for a number of hours at temperatures up to 2800°A, but is most useful when run at about 2500°A. A constant stream of water passes through the cooling system by means of the pipes marked W. A new filament can be inserted in a few moments when one burns out.

Fig. 8
Fig. 8

Graph showing the relation of the color temperature of a tungsten strip to its brightness temperature as measured with an optical pyrometer with red filter (brightness match at wave length 6650A). The energy distribution of the light from the strip in the visible region can then be calculated from Wien’s law, substituting for T in that formula the value of Tc obtained from this curve.

Fig. 9
Fig. 9

Inverted characteristic curve, obtained by plotting the galvanometer deflections of the microphotometer for the various calibration exposures against the transmission factors of the screens or filters in producing these exposures, on double logarithmic paper. In this way the intensities I and I′ of the lines producing galvanometer deflections G and G′ can be read off directly.