| | PAGE |
| [Fig. 1].—The Milky Way | [46] |
| Photo by Easton. |
| [Fig. 2].—Planetary Nebula No. 7009, New General Catalogue | [52] |
| [Fig. 3].—Nebula No. 4594, New General Catalogue | [66] |
| [Fig. 4].—Nebula No. 101 in Messier’s Catalogue | [70] |
| [Fig. 5].—Nebula No. 51 in Messier’s Catalogue | [71] |
| [Fig. 6].—Milky Way Between Cassiopeia and Swan | [76] |
| According to Wolf. |
| [Fig. 7].—Milky Way in Eagle and Sagittarius | [76] |
| According to Wolf. |
| [Fig. 8].—The “trifid” Hole in Eagle | [77] |
| According to Wolf. |
| [Fig. 9].—Tarim River With Lakes and Bayirs | [96] |
| According to Sven Hedin. |
| [Fig. 10].—The Former Lake Bonneville in Utah | [106] |
| [Fig. 11].—Jupiter, 1909 | [122] |
| According to F. le Coultre. |
| [Fig. 12].—Saturn, 1909 | [123] |
| According to F. le Coultre. |
| [Fig. 13].—Spectra of the Major Planets | [124] |
| According to V. M. Slipher. |
| [Fig. 14].—Venus Observed by Langley in 1882 | [136] |
| [Fig. 15].—Rock Fissure at Hango, Sweden | [204] |
| Photo by I. I. Sederholm. |
| [Fig. 16].—Earthquake Centers in Calabria | [205] |
| According to I. I. Sederholm. |
| [Fig. 17].—Maps of Mars by Schiaparelli and Antoniadi | [At the end] |
| [Fig. 17a].—Maps of Mars by Schiaparelli and Antoniadi | [At the end] |
| [Fig. 18].—Photo of Mars by Lampland | [210] |
| [Fig. 19].—Mars on April 8, 1909 | [210] |
| According to Quenisset. |
| [Fig. 20].—The South Pole Spot on Mars, 1909 | [210] |
| According to Jarry Desloges. |
| [Fig. 21].—Sandstorm on Mars, 1909 | [210] |
| According to Antoniadi. |
| [Fig. 22].—Cloud on Edge of Mars, the 7th of March, 1901 | [216] |
| According to Molesworth. |
| [Fig. 23].—Mars, July 11, 1907 | [216] |
| According to Lowell. |
| [Fig. 24].—Mars, October 6, 1909 | [216] |
| According to Antoniadi. |
| [Fig. 25].—Mercury | [230] |
| According to Lowell. |
| [Fig. 26].—The Moon near the Crater Tycho | [230] |
| Photo from Yerkes Observatory. |
| [Fig. 27].—Mare Serenitatis and Mare Tranquillitatis | [231] |
| Photo from Yerkes Observatory. |
| [Fig. 28].—The Moon near its South Pole | [240] |
| Photo from Yerkes Observatory. |
| [Fig. 29].—The Lunar Crater Copernicus and Vicinity | [242] |
| Photo from Yerkes Observatory. |