39. Map of the Weald of Kent 284 40. Sketch Map of the Swiss Rivers 291 41. Diagram in illustration of mountain structure 296 42. Sketch Map of the Aar and its tributaries 299 43. River system round Chur, as it used to be 308 44. River system round Chur, as it is 309 45. River system of the Maloya 311 46. Final slope of a river 317 47. Do. do. with a lake 318 48. Diagrammatic section of a valley (exaggerated). _R R_, rocky basis of a valley; _A A_, sedimentary strata; _B_, ordinary level of river; _C_, flood level 329 49. Whitsunday Island. (After Darwin) 359 50. A group of Lunar volcanoes; Maurolycus, Barocius, etc. (After Judd) 380 51. Orbits of the inner Planets. (After Ball) 388 52. Relative distances of the Planets from the Sun. (After Ball) 389 53. Saturn, with the surrounding series of rings. (After Lockyer) 395 54. The Parallactic Ellipse. (After Ball) 413 55. Displacement of the hydrogen line in the spectrum of Rigel. (After Clarke) 416 PLATES BURNHAM BEECHES _Frontispiece_ WINDSOR CASTLE. (From a drawing by J. Finnemore) _To face page_ 13 AQUATIC VEGETATION, RIO. (Published by Spooner and Co.) 145 TROPICAL FOREST, WEST INDIES. (After Kingsley) 179 SUMMIT OF MONT BLANC 203 THE MER DE GLACE, MONT BLANC 229 RYDAL WATER. (From a photograph by Frith and Co., published by Spooner and Co.) 247 WINDERMERE 253 VIEW IN THE VALAIS BELOW ST. MAURICE 264 VIEW UP THE VALAIS FROM THE LAKE OF GENEVA 268 THE LAND'S END. (From a photograph by Frith and Co., published by Spooner and Co.) 334 VIEW OF THE MOON NEAR THE THIRD QUARTER. (From a photograph by Prof. Draper) 371 CHAPTER I INTRODUCTION