ILLUSTRATIONS. xvii 



FIG. PACK' 



51. The same Prominence fifteen minutes afterwards 118 



52. Non-coincidence of Bright and Dark F Line 119 



53. Contortions of F Line in a Prominence 120 



54. Contortions of the Hydrogen Lines 120 



55. Contortions of the Hydrogen Lines ., 121 



56. Contortions of F Line on Disc 122 



57. Contortions of F Line on Disc, in connection with Spots and Up-rushes 



of Bright Hydrogen 122 



58. Motion Forms and Lozenges 123 



59. Arrangement for Projecting an Image of a Candle Flame on the Slit- 



plate of a Spectroscope 140 



60. Showing Arrangement of Lens with Large Spectroscope 141 



61. Arrangement for obtaining Long and Short Lines. Image of the Hori- 



zontal Arc on Slit-plate of Spectroscope 143 



62. Long and Short Lines 144 



63. Spectrum of Sodium, showing the Long and Short Lines 145 



64. Arrangement for Projecting the Long and Short Lines on a Screen . . 146 



65. Copy of Dr. Miller's Spectrum of Cadmium, showing the Dots .... 147 



66. The Sun and its Atmosphere on Kirchhoff's Hypothesis 163 



67. Diagram showing that if the Sun's Atmosphere consists of Layers the 



Lines will extend down to the Solar Spectrum 164 



68. Spectral Phenomena on the Assumption of three Layers 164 



69. Imagined Stratification of the Solar Atmosphere 169 



70. Stratification of the Solar Atmosphere Disturbed by the Upheaval of a 



Prominence 170 



71. Fluted Spectrum of Iodine (Thalen) ...... * 180 



72. Carbon Flutings 180 



73. Huggms's Stellar Spectra 188 



74. Three Chief Types of Stellar Spectra 189 



75. The Varying Intensities of the Lines of Calcium as seen under different 



conditions - . "V 194 



76. Various Intensities of the Lines of Magnesium as seen under different 



conditions 196 



77. Showing the Various Intensities of the Lines of Lithium under different 



conditions 197 



78. Wave-length Map of the Solar Spectrum 210 



79. Map of the Infra-red portion of the Solar Spectrum, photographed by- 



Captain Abney . . . -. , 21 



b 



