Plate III
Chart of the Moon, showing the Principal Formations seen on its Surface
The dark areas are termed seas, though there is no water on the moon. The many small rings are ring-mountains and ring-plains. (The North Pole is at the top.
Plate IV
Index Map to Chart of the Moon
| 1. | Bay of Rainbows | 18. | Apennine Mountains | 35. | Alphonsus |
| 2. | Plato | 19. | Sea of Serenity | 36. | Arzachel |
| 3. | Sea of Cold | 20. | Haemus Mountains | 37. | Theophilus |
| 4. | Alps Mountains | 21. | Sea of Conflicts | 38. | Cyrillus |
| 5. | Great Alpine Valley | 22. | Proclus | 39. | Catherina |
| 6. | Cassini | 23. | Sea of Tranquillity | 40. | Sea of Nectar |
| 7. | Autolycus | 24. | Sea of Fertility | 41. | Langrenus |
| 8. | Aristillus | 25. | Hevel | 42. | Vendelinus |
| 9. | Archimedes | 26. | Kepler | 43. | Petavius |
| 10. | Timocharis | 27. | Grimaldi | 44. | Schickard |
| 11. | Lambert | 28. | Flamsteed | 45. | Wargentin |
| 12. | Euler | 29. | Bonpland | 46. | Tycho |
| 13. | Sea of Showers | 30. | Gassendi | 47. | Maurolycus |
| 14. | Aristarchus | 31. | Sea of Vapours | 48. | Clavius |
| 15. | Herodotus | 32. | Hipparchus | 49. | Newton |
| 16. | Ocean of Storms | 33. | Albategnius | 50. | Straight Wall |
| 17. | Copernicus | 34. | Ptolemæus | 51. | Sea of Moisture |
| 52. | Sea of Clouds |
Proceeding on our tour of inspection, we crossed the Ocean of Storms to a point near the central part of the lunar surface, and I showed them the fine walled plain called Ptolemæus. This is 115 miles in diameter, and contains an area as large as the combined areas of Yorkshire, Lancashire, and Westmorland, its highest peak being 9000 feet in altitude. It forms the most northerly of a line of walled plains, the most southerly being Arzachel, which is sixty-six miles in diameter, and has a very depressed floor; while one peak on the walls rises to a height of 13,000 feet.
Passing farther west, we next examined another splendid group of three ring-mountains, arranged in a line running nearly north and south, viz. Theophilus, Cyrillus, and Catherina. The first is the most northerly, and is about sixty-four miles in diameter, with several very high peaks—one rising as much as 18,000 feet, and two on the opposite side being 16,000 and 14,000 feet high respectively. Even the central mountain is very large in area, and 6000 feet high. "That," I remarked to M'Allister, "is nearly half as high again as Ben Nevis, the highest mountain in Scotland, which is, after all, only 4400 feet high."
"Ben Nevis, Professor, is 4406 feet high!" corrected M'Allister.