50. GREENWICH RECORD OF DISTURBANCE OF MAGNETIC NEEDLE, NOV. 16 AND 17, 1882 81 51. SUN-SPOTS AND MAGNETIC VARIATIONS 87 52. GREENWICH MAGNETIC OBSERVATIONS, AUG. 3 AND 5, 1872 89 53. ONE CUBIC CENTIMETRE 93 54. POUILLET’S PYRHELIOMETER 93 55. BERNIÈRES’S GREAT BURNING-GLASS 103 56. A “POUR” FROM THE BESSEMER CONVERTER 105 57. PHOTOMETER-BOX 108 58. MOUCHOT’S SOLAR ENGINE 109 59. ERICSSON’S NEW SOLAR ENGINE, NOW IN PRACTICAL USE IN NEW YORK 113 60. SATURN 119 61. THE EQUATORIAL TELESCOPE AT WASHINGTON 122 62. JUPITER, MOON, AND SHADOW 125 63. THREE VIEWS OF MARS 129 64. MAP OF MARS 129 65. THE MOON 137 66. THE FULL MOON 141 67. GLASS GLOBE, CRACKED 145 68. PLATO AND THE LUNAR ALPS 149 69. THE LUNAR APENNINES: ARCHIMEDES 153 70. VESUVIUS AND NEIGHBORHOOD OF NAPLES 157 71. PTOLEMY AND ARZACHEL 161 72. MERCATOR AND CAMPANUS 165 73. WITHERED HAND 168 74. IDEAL LUNAR LANDSCAPE AND EARTH-SHINE 169 75. WITHERED APPLE 171 76. GASSENDI. NOV. 7, 1867 173 77. THE CAMP AT MOUNT WHITNEY 177 78. VESUVIUS DURING AN ERUPTION 183 79. METEORS OBSERVED NOV. 13 AND 14, 1868, BETWEEN MIDNIGHT AND FIVE O’CLOCK, A. M. 189 80. COMET OF DONATI, SEPT. 16, 1858 201 81. “A PART OF A COMET” 203 82. COMET OF DONATI, SEPT. 24, 1858 205 83. COMET OF DONATI, OCT. 3, 1858 209 84. COMET OF DONATI, OCT. 9, 1858 213 85. COMET OF DONATI, OCT. 5, 1858 217 86. TYPES OF STELLAR SPECTRA 222 87. THE MILKY WAY 225