Mapping the spectrum: Techniques of Representation

Mapping the spectrum: Techniques of Representation in Research and Teaching by Klaus Hentschel Institut f¨ ur Wissenschaftsgeschichte Humboldtallee 11 D-37073 G¨ottingen, F.R.G. (currently Fellow at the Dibner Institute, MIT)

Contents 1 Introduction 1.1 The study of visual representations in 1.2 Spectroscopy as a visual culture . . . 1.3 The mapping metaphor . . . . . . . . 1.4 The rhetorics of spectra . . . . . . . 1.5 The structure of this book . . . . . . 1.6 Acknowledgments . . . . . . . . . . . 1.7 Archival abbreviations . . . . . . . .

science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2 The 2.1 2.2 2.3 2.4 2.5 2.6 2.7

spectrum in historical context “The Phænomena of Colours” . . . . . . . . . . . . . The dark lines . . . . . . . . . . . . . . . . . . . . . . Early modes of representing the spectrum . . . . . . The tardy emergence of spectrum analysis . . . . . . Numerical scales in spectrum maps . . . . . . . . . . Prisms versus diffraction gratings . . . . . . . . . . . Extension of the spectral range and its interpretation 2.7.1 William Herschel’s heat intensity curve . . . . 2.7.2 John Herschel’s thermograph . . . . . . . . . 2.8 The phosphorogenic spectrum . . . . . . . . . . . . . 2.9 New instruments for exploring the heat spectrum . .

3 The 3.1 3.2 3.3 3.4 3.5

interplay of representational form and purpose Enlarging comprehensive maps . . . . . . . . . . . . . Magnifying interesting segments: zooming . . . . . . Abstracting spectra: condensing . . . . . . . . . . . . Distilling out the metaphysical . . . . . . . . . . . . . The phenomenology of the rainband . . . . . . . . . .

4 Line matters 4.1 Engraving and etching . . . . . . . . . 4.2 Lithography . . . . . . . . . . . . . . . 4.3 Prints on more than one stone . . . . . 4.4 Woodcuts and symbolic representations 4.5 Spectroscopic portraiture . . . . . . . . 5 The 5.1 5.2 5.3 5.4

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material culture of printing The social setting . . . . . . . . . . . . . . . . . . . . . . . Photomechanical printing techniques . . . . . . . . . . . . Transfer of skills from topographic to spectrographic maps The economy of the printing trade . . . . . . . . . . . . . . I

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1 1 4 8 12 14 17 18

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20 20 31 33 44 46 50 55 55 57 60 63

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79 80 87 96 99 102

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108 . 109 . 116 . 120 . 124 . 126

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137 . 137 . 151 . 159 . 165

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Contents

II 6 The 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9

rise of photography Early techniques . . . . . . . . . . . . . . . . . . . . . . . . . The dry-plate spectrum . . . . . . . . . . . . . . . . . . . . . The photographer’s self-image . . . . . . . . . . . . . . . . . . Early photographs of the solar spectrum, 1839–1846 . . . . . . Early work in color . . . . . . . . . . . . . . . . . . . . . . . . Scientific applications since 1860 . . . . . . . . . . . . . . . . . Draper’s diffraction spectrum photograph and Albertype, 1873 The virtues and pitfalls of spectrum photography . . . . . . . Photographic maps of the normal solar spectrum 1885–1900: Clean, Higgs . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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7 Photochemical experimentation, infrared, and the turn towards photometry 7.1 Hermann Wilhelm Vogel’s discovery of sensitizers in 1873 . . . . 7.2 Abney’s infrared photographs and emulsions as an art . . . . . . 7.3 Further improvements in infrared-sensitive emulsions . . . . . . 7.4 The introduction of photometry . . . . . . . . . . . . . . . . . . 7.4.1 Gauging the spectral line intensity in the 19th century . 7.4.2 Towards automated recording techniques in the infrared 7.4.3 Photochemical and photometric registration methods . . 7.5 Prevalence of photometric techniques in the 20th century . . . . 8 Research applications: Pattern recognition 8.1 Qualitative spectrum analysis: element identification . . . . . 8.2 Strategies for series identification: Hinrichs, Balmer, Rydberg 8.3 Stoney’s search for harmonics and wavelength reciprocals . . . 8.4 Homologous spectra: Lecoq, Ciamician, Hartley . . . . . . . . 8.5 The green CO band: Piazzi Smyth and A. Herschel 1883 . . . 8.6 The oxygen band doublets: George Higgs 1893 . . . . . . . . . 8.7 Quantitative emission spectroscopy . . . . . . . . . . . . . . . 8.8 Stellar spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . 9 In the classroom laboratory 9.1 Textbooks and laboratory course manuals . . . . . . . . . . . 9.2 The case of the Massachusetts Institute of Technology . . . . . 9.3 Laboratory training at other universities in the United States . 9.4 Mapping spectra in classroom exercises . . . . . . . . . . . . . 9.5 Sarah Whiting’s courses at Wellesley College . . . . . . . . . . 9.6 Teaching the classification of stellar spectra . . . . . . . . . . 9.7 The Harvard Students Astronomical Laboratory . . . . . . . . 9.8 Spectroscopy at high schools and its further dissemination . . ´ 9.9 The case of France: the Ecole Polytechnique . . . . . . . . . . 10 Epilogue 10.1 Spectroscopy: not a discipline . . . . . . . . . . 10.2 Implications of spectroscopy as a visual culture 10.3 The making of a spectroscopist . . . . . . . . . 10.4 Scopic regimes and spectro-scopic domains . . .

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172 . 172 . 185 . 186 . 190 . 200 . 205 . 209 . 216

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243 244 249 254 260 260 262 269 271

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286 . 286 . 289 . 302 . 304 . 311 . 316 . 319 . 338

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357 . 359 . 363 . 370 . 375 . 379 . 386 . 389 . 392 . 404

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411 . 411 . 416 . 418 . 424

Contents 10.5 Persistent modes of visual representations . . . . . . . 10.6 Visual analogy . . . . . . . . . . . . . . . . . . . . . . 10.7 Interdependence of representation and research strategy 10.8 Periodization . . . . . . . . . . . . . . . . . . . . . . . 10.9 The resplendent band: the aesthetic appeal of spectra . 10.10Taking the mapping metaphor seriously . . . . . . . . .

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429 430 439 441 446 450

List of Figures 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.34 2.36 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 3.1 3.2 3.3

Two drawings of spectrum observations by Leonardo . . . . . . . . . . . . . . . Della Porta’s conceptualization of prismatic color as condensation, 1593 . . . . . Descartes’s apparatus to measure the index of refraction, 1637 . . . . . . . . . . Descartes’s prismatic experiment with solar light . . . . . . . . . . . . . . . . . Newton’s experimentum crucis with the solar spectrum, 1672 . . . . . . . . . . A later variant from Newton’s correspondence, 1721 . . . . . . . . . . . . . . . . Newton’s optical analogue to the diatonic scale, 1704 . . . . . . . . . . . . . . . Newton’s parallelogram representation of the solar spectrum, 1704 . . . . . . . . Erxleben’s seven homogenized primary colors, 1772 . . . . . . . . . . . . . . . . Hassenfratz’s absorption spectra as superimposed primary colors, 1808 . . . . . Fraunhofer’s pencil drawing for his solar spectrum, c. 1814 . . . . . . . . . . . . Absorption spectra schematically drawn by Brewster, 1822 . . . . . . . . . . . . J. Herschel’s continuous curves of absorption in various media, 1830 . . . . . . . David Alter’s tabular line count of spark spectra by color, 1854 . . . . . . . . . Langley’s experimental setup with both a prism and a grating, 1883 . . . . . . . Langley’s graph of the solar spectrum into the infrared, up to 28 000 ˚ A . . . . . Miller’s lithograph of molecular flame spectra, 1845 . . . . . . . . . . . . . . . . J.W. Draper’s diagram of continuous flame spectra, 1848 . . . . . . . . . . . . . Swan’s comparison of the solar spectrum with hydrocarbon spectra, 1857 . . . . Bunsen’s spectra of alkali metals and alkaline earths, 1860 . . . . . . . . . . . . Diacon’s copper chloride spectrum, 1865 . . . . . . . . . . . . . . . . . . . . . . Bunsen and Kirchhoff’s second spectroscope, 1861 . . . . . . . . . . . . . . . . . Comparison of spectra generated by flint and crown-glass prisms . . . . . . . . . Bunsen’s symbolic plot of emission spectra, 1863 . . . . . . . . . . . . . . . . . The spectrum of barium oxide compared with other compounds as plotted by Mitscherlich, 1864 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kirchhoff’s four-prism Steinheil spectroscope . . . . . . . . . . . . . . . . . . . . Comparison of the scales of a prismatic and a diffraction spectrum . . . . . . . W. Herschel’s experimental setup, 1800 . . . . . . . . . . . . . . . . . . . . . . . W. Herschel’s comparison of visual and thermometric intensity curves . . . . . . J. Herschel’s thermograph and photograph of the solar spectrum . . . . . . . . . J. Herschel’s interpretation of the thermograph, 1840 . . . . . . . . . . . . . . . Coexistence of luminous, thermal, and chemical spectra . . . . . . . . . . . . . . Stokes’s mapping of the extreme violet and the “invisible region beyond” the optical solar spectrum, 1852 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lamansky’s plot of the energy distribution in the near infrared of the solar prismatic spectrum, 1872 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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21 22 23 23 26 27 28 29 30 31 34 37 38 40 65 67 68 69 69 70 70 71 71 71

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72 73 73 74 75 76 76 77

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Comparison drawings of the A group, 1861–1886 . . . . . . . . . . . . . . . . . . 88 Browning’s automatic spectroscope with a six-prism chain . . . . . . . . . . . . . 91 A typical lantern projection apparatus . . . . . . . . . . . . . . . . . . . . . . . . 94 IV

List of Figures 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.3 4.4 4.5 4.6

V

Drawings of the A group between 1860 and 1881, magnified and redrawn same scale by Piazzi Smyth, 1882 . . . . . . . . . . . . . . . . . . . . . . Comparison of the solar spectrum at different times of day, 1871 . . . . . Section of Thollon’s comparative atlas of the solar spectrum, 1890 . . . . Direct-vision rainband spectroscope . . . . . . . . . . . . . . . . . . . . . The rainband as seen in various weather conditions . . . . . . . . . . . .

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97 100 101 103 105

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109 109 110 111 113

4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16

Instruments and hand positioning for copper engraving . . . . . . . . . . . . . . Comparison of line profiles in engraving and etching . . . . . . . . . . . . . . . Shading details of the Sr and Mn spectra in a steel engraving, 1864 . . . . . . . Cross-hatching to render shades of gray in spectrum bands, 1871 . . . . . . . . Detail of Fraunhofer’s spectrum map with superimposed shading, 1814 . . . . . Engraver’s roulette and sample use of it in Lecoq de Boisbaudran’s atlas of band spectra, 1874 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lecoq de Boisbaudran’s pencil sketch of the same motif, 1872 . . . . . . . . . . Lithographic line patterns drawn with various implements . . . . . . . . . . . . Two different types of drawing pens . . . . . . . . . . . . . . . . . . . . . . . . Sample section of Kirchhoff’s map of the solar spectrum, 1861 . . . . . . . . . . A symbolic notation for the spectral sensitivity of collodion emulsions . . . . . . Piazzi Smyth’s conventions for the representation of spectral line intensity . . . Section from Cornu’s map of the near-ultraviolet solar spectrum, 1874 . . . . . Thollon’s second prism setup, 1879 . . . . . . . . . . . . . . . . . . . . . . . . . Thollon’s final prism-chain design, 1879 . . . . . . . . . . . . . . . . . . . . . . Thollon’s final experimental setup, 1879 . . . . . . . . . . . . . . . . . . . . . .

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115 115 129 130 130 131 131 131 133 134 135

5.1 5.2 5.3 5.4 5.5

Reprint of Kirchhoff’s plates by the ‘proc´ed´e Dulos’, 1864 Joseph Albert’s Munich Printing House, c. 1870 . . . . . . Photogalvanographic print of a sunspot photograph, 1862 Cartographic camera in military use, about 1885 . . . . . Ruling machine for cartography . . . . . . . . . . . . . . .

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142 155 157 161 164

6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10

Microphotograph of a silver-bromide emulsion . . . . . . . . . . . . . . . . . . . E. Becquerel’s dark lines beyond the violet of the visible spectrum, 1842 . . . . J.W. Draper’s daguerreotype of the solar spectrum, 1842 . . . . . . . . . . . . . Draper’s representation of the optical and tithonic solar spectrum, 1843 . . . . . Hunt’s survey of contemporary photochemical experiments, 1844 . . . . . . . . The action of the solar spectrum on vegetable dyes, Somerville, 1846 . . . . . . Hunt’s color photograph of the solar spectrum, 1840 . . . . . . . . . . . . . . . Mezzotint engraving of ultraviolet spark spectra of zinc and magnesium . . . . . Segment of Rutherfurd’s photograph of the solar spectrum, c. 1864 . . . . . . . The violet and ultraviolet solar spectrum from Fraunhofer line G to the line complex R, 1862 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Henry Draper’s wet collodion photograph and magnified pencil drawing of the solar diffraction spectrum, 1872 . . . . . . . . . . . . . . . . . . . . . . . . . . . Albertype of H. Draper’s photograph of the solar spectrum, 1873 . . . . . . . . Photographic retouching procedures . . . . . . . . . . . . . . . . . . . . . . . . Sample plate from Capron’s atlas of arc and spark spectra, 1877 . . . . . . . . . Comparison of Lockyer’s ink drawing and photograph of the solar spectrum near H, 1881 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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184 192 194 196 197 199 201 205 207

6.11 6.12 6.13 6.14 6.15

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VI 6.16 6.17 6.18 6.19 6.20 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11 7.12 7.13 7.14 7.15 7.16 7.17 7.18 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 8.15

List of Figures A photomechanical print compared with its lithographic redrawing, 1890 . . . . Detail from the second series of Rowland’s Photographic Map of the Normal Solar Spectrum, 1888 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Higgs’s mounting for a concave grating, 1894 . . . . . . . . . . . . . . . . . . . Higgs’s photograph of the b group, 1894 . . . . . . . . . . . . . . . . . . . . . . Detail from Henry Crew’s photographic atlas of the zinc spectrum, 1895 . . . . H.W. Vogel’s small and large spectrographs . . . . . . . . . . . . . . . . . . . . Comparative plot of the sensitivity of a dyeless gelatino-bromide plate, and enhanced sensitivities with various dyes . . . . . . . . . . . . . . . . . . . . . . . . Abney’s comparison of Herschel’s thermograph with his own map of the infrared solar spectrum, 1880 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The stepwise progress of photography of the infrared spectrum after 1900 . . . . Wedge spectrograph and wedge spectrograms of various types of photographic plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cyanine dyes with methine chains of increasing length . . . . . . . . . . . . . . Fluctuations of the galvanometer needle connected to a bolograph . . . . . . . . Langley’s final bolometric curve of the infrared spectrum, 1900 . . . . . . . . . Langley’s conversion of bolometric curves to normal spectra . . . . . . . . . . . Bolometric curve, 1929 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scheme of a photocell and electric amplification of the photocurrent . . . . . . . Diagram of Koch’s registering microphotometer, 1912 . . . . . . . . . . . . . . . Photometric curve of a Zeeman-split spectrum line . . . . . . . . . . . . . . . . Spectrophotometric wedge photographs . . . . . . . . . . . . . . . . . . . . . . . Utrecht apparatus for direct intensity recordings, 1938 . . . . . . . . . . . . . . Sample from the Utrecht Photometric Atlas of the Solar Spectrum, 1940 . . . . Transformation of a line profile into a microphotometer output function . . . . . Correction for the change in intensity of the continuous background . . . . . . . Balmer’s Pythagorean approach to series lines . . . . . . . . . . . . . . . . . . . Huggins’s representation of the hydrogen series in α Lyrae, 1879 . . . . . . . . . Balmer’s geometric approach to series lines . . . . . . . . . . . . . . . . . . . . . Two sketches from the Balmer papers, c. 1884 . . . . . . . . . . . . . . . . . . . Rydberg’s plot of the wave numbers of spectrum lines for the alkaline metal series, 1889 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lecoq de Boisbaudran’s pencil sketches of the N2 and BaCl spectra, 1872 . . . . Homologies in the spectra of Mg, Zn, and Cd, Hartley, 1883 . . . . . . . . . . . Telescope mounting, micrometer screw, recording barrel, and prism setup for Piazzi Smyth’s measurements, 1883 . . . . . . . . . . . . . . . . . . . . . . . . . Higgs’s wavelength plot of the oxygen band at 6900 ˚ A . . . . . . . . . . . . . . Lwe’s atlas of the ultimate lines, 1928 . . . . . . . . . . . . . . . . . . . . . . . Diagram illustrating Gerlach’s relative determination of the concentration of an impurity in a sample, 1925 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Practical example of identifying pairs of equally intense lines at various concentrations of Pb in Sn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Huggins’s star spectroscopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Redshift of the hydrogen line Hβ in the spectrum of Sirius, 1868 . . . . . . . . . Stellar field photographed by the objective-prism method . . . . . . . . . . . . .

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228 237 238 242

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259 260 263 264 267 269 274 275 276 278 280 281 283 284

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293 294 295 297

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330 340 344 347

List of Figures

VII

8.16

A.J. Cannon inspecting a stellar spectrum photograph, c. 1940 . . . . . . . . . . 350

9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11

General physics laboratory, MIT Boston campus, 1890s . . . . . . . . Main physics lecture hall at MIT with posters of the spectrum, 1890s Photographic dark room in the MIT laboratory of general physics . . Student exercise: wavelength determination in the sodium spectrum . Charting of absorption spectra in laboratory exercises in chemistry, c. Students at Wellesley College with physical laboratory instruments . Physics labs and Rowland concave grating with heliostat at Wellesley Student drawings of spectra from Whiting’s lab session, c. 1890 . . . Homemade fluid prism and box spectroscope for student exercises . . Student observing the reversion of the sodium line in the flame . . . Homemade spectroscopic slit for observing Fraunhofer lines . . . . .

10.1 10.2

Level diagram and frequency plot of the Balmer series, 1937 . . . . . . . . . . . Graph with relative weights of symbolic and iconic signs in visual representations of emission spectra 1855–1955 . . . . . . . . . . . . . . . . . . . . . . . . . . . . Balmer’s drawing of a perspectivally shortened stairway, 1887 . . . . . . . . . . Balmer’s tangent method, 1884 . . . . . . . . . . . . . . . . . . . . . . . . . . . Kayser’s composite photograph of the cyanogen band spectrum, 1889 . . . . . . Piazzi Smyth’s drawing of the Fraunhofer A and a bands, 1877 . . . . . . . . . Instruction sheet on various techniques of drawing topographic maps, 1854 . . .

10.3 10.4 10.5 10.6 10.7

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366 368 369 374 378 380 381 383 399 400 400

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437 437 438 446 447 452

List of Tables 3.1

Interplay between research objective and representational type . . . . . . . . . . . 86

5.1 5.2 5.3 5.4 5.5 5.6

Statistics on Berlin lithographers, copper engravers, and photographers according to the Berliner Adressbuch, 1836–1905 . . . . . . . . . . . . . . . . . . . . . . . . Statistics of printers and engravers in London 1852–1900 . . . . . . . . . . . . . . Photographic agencies and artisanal workshops in Berlin, 1875 . . . . . . . . . . . Survey of photomechanical printing techniques . . . . . . . . . . . . . . . . . . . . The various expenses connected with the production of a geographic map in 1793 Cost comparison for copper and steel plates, 1861 . . . . . . . . . . . . . . . . . .

6.1 6.2

Main photographic processes, 1839–1879 . . . . . . . . . . . . . . . . . . . . . . . 173 List of absorbents used by Rowland to filter parts of the spectrum for photography230

7.1

Survey of photometric atlases 1929–1981 . . . . . . . . . . . . . . . . . . . . . . . 282

8.1 8.2 8.3

Pollok’s nomenclature for the sensitive spectrum lines of metals in solution, 1907 . Statistics on publications in spectrochemical analysis 1920–55 . . . . . . . . . . . Translation between the stellar spectrum classifications of Secchi, Vogel, and the Harvard System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Survey of atlases of stellar spectra 1890–1978 . . . . . . . . . . . . . . . . . . . .

8.4

VIII

145 146 148 152 166 168

321 334 349 356