Mapping the spectrum: Techniques of visual ...

Mapping the spectrum: Techniques of visual representation in research and teaching Klaus Hentschel

OXFORD University Press 18th October 2001

iii

CONTENTS

List of illustrations

ix

List of tables

xiii

1

Introduction 1.1 The study of visual representations in science 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

1 1 4 9 13 15 18 20

2

The spectrum in historical context 2.1 “The Phænomena of Colours” 2.2 The dark lines 2.3 Early modes of representing the spectrum 2.4 The tardy emergence of spectrum analysis 2.5 Numerical scales in spectrum maps 2.6 Prisms versus diffraction gratings 2.7 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

21 21 32 34 45 48 55 60 61 64 68 72

3

The interplay of representational form and purpose 3.1 Enlarging comprehensive maps 3.2 Magnifying interesting segments: zooming 3.3 Abstracting spectra: condensing 3.4 Distilling out the metaphysical 3.5 The phenomenology of the rainband

80 81 89 99 101 104

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 of spectra 4.5 Spectroscopic portraiture

111 111 119 124 130 132

vi

CONTENTS

5

The material culture of printing 5.1 The social setting 5.2 Photomechanical printing techniques 5.3 Transfer of skills from topographic to spectrographic maps 5.4 The economy of the printing trade

140 140 155 163 169

6

The rise of photography 6.1 Early techniques 6.2 The dry-plate spectrum 6.3 The photographer’s self-image 6.4 Early photographs of the solar spectrum, 1839–1846 6.5 Early work in color 6.6 Scientific applications since 1860 6.7 Draper’s diffraction spectrum photograph and Albertype, 1873 6.8 The virtues and pitfalls of spectrum photography 6.9 Photographic maps of the normal solar spectrum 1885–1900: Rowland, McClean, Higgs

176 176 187 189 193 203 208 213 219

7

229

Photochemical experimentation, infrared exploration, 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

247 248 254 258 264 265 267 273 276

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

290 290 293 305 307 314 320 323 343

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

362 364 368 376 381 385 393

CONTENTS

9.7 9.8 9.9

The Harvard Students Astronomical Laboratory Spectroscopy at high schools and its further dissemination The case of France: the École Polytechnique

vii

396 399 413

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 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 10.10 Taking the mapping metaphor seriously

420 420 425 427 434 440 442 448 450 455 460

Appendix 1 Survey of maps of the solar spectrum 1802–1918

465

Appendix 2 Survey of maps of terrestrial spectra 1835–1949

467

Bibliography Bibliographic Abbreviations References

471 471 473

Index

551

LIST OF ILLUSTRATIONS 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 2.15 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 2.33 2.34 2.35 2.36 3.1

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 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 Wiring diagrams for three types of bolometers Langley’s experimental setup with both a prism and a grating, 1883 Langley’s graphic procedure for converting a prismatic spectrum into a wavelength plot, 1883 Langley’s graph of the solar spectrum into the infrared, up to 28 000 Å Comparison drawings of the A group, 1861–1886

22 23 24 25 27 28 29 30 31 32 35 37 38 40 43 44 46 47 48 49 50 52 53 54 56 62 63 65 66 68 70 73 74 76 78 79 90

x 3.2 3.3 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 5.1 5.2 5.3 5.4 5.5 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16

ILLUSTRATIONS Browning’s automatic spectroscope with a six-prism chain A typical lantern projection apparatus Drawings of the A group between 1860 and 1881, magnified and redrawn to the 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 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 Reprint of Kirchhoff’s plates by the ‘procédé 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 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 A photomechanical print compared with its lithographic redrawing, 1890

93 96 99 102 103 105 107 112 112 113 114 116 118 118 122 123 125 131 131 134 136 138 138 146 159 161 165 168 186 195 197 199 200 202 205 209 210 212 215 219 222 224 225 228

ILLUSTRATIONS 6.17 Detail from the second series of Rowland’s Photographic Map of the Normal Solar Spectrum, 1888 6.18 Higgs’s mounting for a concave grating, 1894 6.19 Higgs’s photograph of the b group, 1894 6.20 Detail from Henry Crew’s photographic atlas of the zinc spectrum, 1895 7.1 H.W. Vogel’s small and large spectrographs 7.2 Comparative plot of the sensitivity of a dyeless gelatino-bromide plate, and enhanced sensitivities with various dyes 7.3 Abney’s comparison of Herschel’s thermograph with his own map of the infrared solar spectrum, 1880 7.4 The stepwise progress of photography of the infrared spectrum after 1900 7.5 Wedge spectrograph and wedge spectrograms of various types of photographic plates 7.6 Cyanine dyes with methine chains of increasing length 7.7 Fluctuations of the galvanometer needle connected to a bolograph 7.8 Langley’s final bolometric curve of the infrared spectrum, 1900 7.9 Langley’s conversion of bolometric curves to normal spectra 7.10 Bolometric curve, 1929 7.11 Scheme of a photocell and electric amplification of the photocurrent 7.12 Diagram of Koch’s registering microphotometer, 1912 7.13 Photometric curve of a Zeeman-split spectrum line 7.14 Spectrophotometric wedge photographs 7.15 Utrecht apparatus for direct intensity recordings, 1938 7.16 Sample from the Utrecht Photometric Atlas of the Solar Spectrum, 1940 7.17 Transformation of a line profile into a microphotometer output function 7.18 Correction for the change in intensity of the continuous background 8.1 Balmer’s Pythagorean approach to series lines 8.2 Huggins’s representation of the hydrogen series in α Lyrae, 1879 8.3 Balmer’s geometric approach to series lines 8.4 Two sketches from the Balmer papers, c. 1884 8.5 Rydberg’s plot of the wave numbers of spectrum lines for the alkaline metal series, 1889 8.6 Lecoq de Boisbaudran’s pencil sketches of the N2 and BaCl spectra, 1872 8.7 Homologies in the spectra of Mg, Zn, and Cd, Hartley, 1883 8.8 Telescope mounting, micrometer screw, recording barrel, and prism setup for Piazzi Smyth’s measurements, 1883 8.9 Higgs’s wavelength plot of the oxygen band at 6900 Å 8.10 Löwe’s atlas of the ultimate lines, 1928 8.11 Diagram illustrating Gerlach’s relative determination of the concentration of an impurity in a sample, 1925 8.12 Practical example of identifying pairs of equally intense lines at various concentrations of Pb in Sn 8.13 Huggins’s star spectroscopes 8.14 Redshift of the hydrogen line Hβ in the spectrum of Sirius, 1868 8.15 Stellar field photographed by the objective-prism method 8.16 A.J. Cannon inspecting a stellar spectrum photograph, c. 1940 9.1 General physics laboratory, MIT Boston campus, 1890s 9.2 Main physics lecture hall at MIT with posters of the spectrum, 1890s 9.3 Photographic dark room in the MIT laboratory of general physics

xi

231 241 242 245 249 253 257 261 263 264 268 269 271 273 278 279 281 282 285 285 287 288 297 299 300 301 302 309 314 315 322 331 332 335 345 348 352 354 372 373 375

xii 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 10.1 10.2 10.3 10.4 10.5 10.6 10.7

ILLUSTRATIONS Student exercise: wavelength determination in the sodium spectrum Charting of absorption spectra in laboratory exercises in chemistry, c. 1890 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 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

Color Plates Color plates appear between pages 34 and 35 I II II III III IV IV

Fraunhofer’s map of the solar spectrum. Rare handcolored version and published black and white print, drawn and etched by Fraunhofer, 1814 Top: Iris print of W.A. Miller’s lithographic plate of flame spectra of various metallic compounds, 1845 Bottom: Bunsen’s chart of characteristic lines in emission spectra of alkali metals and alkaline earths, 1860 Top: Brewster’s handcolored drawings of absorption spectra, 1823 Bottom: Kirchhoff’s chromolithograph of the solar spectrum, printed on six stones, 1861 Top: Three of Secchi’s four classes of stellar spectra, engraved and colored by Dulos, 1870 Bottom: Color photographs of arc spectra obtained by Hermann Krone with the Lippmann process, 1892

380 384 387 387 389 407 408 408 438 440 443 444 456 457 461

TABLES Tab. 3.1

Interplay between research objective and representational type

Tab. 5.1

Statistics on Berlin lithographers, copper engravers, and photographers according to the Berliner Adressbuch, 1836–1905

149

Tab. 5.2

Statistics of printers and engravers in London 1852–1900

150

Tab. 5.3

Photographic agencies and artisanal workshops in Berlin, 1875

152

Tab. 5.4

Survey of photomechanical printing techniques

156

Tab. 5.5

The various expenses connected with the production of a geographic map in 1793

170

Tab. 5.6

Cost comparison for copper and steel plates, 1861

172

Tab. 6.1

Main photographic processes, 1839–1879

177

Tab. 6.2

List of absorbents used by Rowland to filter parts of the spectrum for photography

233

Tab. 7.1

Survey of photometric atlases 1929–1981

286

Tab. 8.1

Pollok’s nomenclature for the sensitive spectrum lines of metals in solution, 1907

326

Tab. 8.2

Statistics on publications in spectrochemical analysis 1920–55

338

Tab. 8.3

Translation between the stellar spectrum classifications of Secchi, Vogel, and the Harvard System

353

Survey of atlases of stellar spectra 1890–1978

361

Tab. 8.4

88

Appendix 1 Survey of maps of the solar spectrum 1802–1900

465

Appendix 2 Survey of maps of terrestrial spectra 1835–1949

467