Geological Formation of Mexico--The _Tierra Caliente_--The _Tierra Templada_--The _Tierra Fria_. The Sylvan Wonders of Sikkim--Changes of the Forest on ascending-- The Torrid Zone of Vegetation--The Temperate Zone--The Coniferous Belt--Limits of Arboreal Vegetation--Animal Life 79 CHAPTER IX. THE KALAHARI AND THE BUSHMEN. Reasons why Droughts are prevalent in South Africa--Vegetation admirably suited to the Character of the Country--Number of Tuberous Roots--The Caffre Water-Melon--The Mesembryanthemums-- The Animal Life of the Kalahari--The Bushmen, a Nomadic Race of Hunters--Their Skill in Hunting--Their Food--Acuteness of their Sight and Hearing--Their Intelligence and Perseverance-- Their Weapons and Marauding Expeditions--Their Voracity--Their Love of Liberty--The Bakalahari--Their Love for Agriculture-- Their Ingenuity in procuring Water--Trade in Skins--Their timidity 85 CHAPTER X. THE SAHARA. Its uncertain Limits--Caravan Routes--Ephemeral Streams--Oases-- Inundations--Luxuriant Vegetation of the Oases contrasted with the surrounding Desert--Harsh contrasts of Light and Shade-- Sublimity of the Desert--Feelings of the Traveller while crossing the Desert--Its charms and terrors--Sand-Spouts--The Simoom--The ‘Sea of the Devil’--The Gazelle--Its chase--The Porcupine--Fluctuation of Animal Life according to the Seasons-- The Tibbos and the Tuaregs--Their contempt of the sedentary Berbers 93 CHAPTER XI. THE BEDOUINS OF ARABIA. The Deserts of Arabia--Sedentary Arabs and Bedouins--Physical Characteristics of the Bedouins--Remarkable acuteness of their Senses--Their Manners--Their intense Patriotism and Contempt of the dwellers in Cities--The Song of Maysunah--Their Wars-- Their Character softened by the Influence of Woman--Their chivalrous Sentiments--The Arab horse--The Camel--Freedom of the Arabs from a Foreign and a Domestic Yoke--The Bedouin Robber--His Hospitality--Mode of Encamping--Death Feuds-- Blood-money--Amusements--Throwing the Jereed--Dances-- Poetry--Story-telling--Language--The Bedouin and the North American Indian 104 CHAPTER XII. GIANT TREES AND CHARACTERISTIC FORMS OF TROPICAL VEGETATION.