CHAPTER VII. 



THE DESERT ZONE. 



Approximate Limits and Position of The Desert Zone. Erroneous 

 Popular Ideas Respecting Deserts. Contours of Desert Territory in the 

 Soudan. Limits of the Tropical Rains. The Nile Region. The 

 Variable Rains of North Africa. The Algerian "Tell." Origin of the 

 Word " Sahara. " Arab Terms Denoting the Different Classes of 

 Desert. Action of Sand under Influence of Wind. Movements of 

 Sand Dunes. Buried Cities in the Desert of Gobi. Sand Storms. 

 Whirlwinds, or Gyrating Storms. Alleged Destruction of the Army of 

 Cambyses in One of These Storms. Account of the Catastrophe Given 

 by Herodotus. Effect of Intense Drought upon the Dead Bodies of 

 Camels, etc. Great Mortality of Animals on Caravan Routes. Losses 

 of Men and Animals by Losing Their Way in Sand Storms. Causes 

 of Sudden Storms in Deserts. Period of the Day when they are 

 Most Prevalent. Description of a Desert Sand Storm. Precautions to 

 be Taken. Sand-Drift as a Rock-carving Agent. Whirlwinds in the 

 Nubian Desert. Pillars of Sand the Supposed Work of Evil Spirits. 

 Arab Superstitions as to Genii, etc. The " Simoon " or Hot Wind. 

 Injury Done by Hot Winds in Australia. Undulatory Motion of These 

 Winds. "Red Fogs." Remarkable Instance of Red Fog at Sea. 

 Some Scientific Aspects of "Dust." Formation and Collapse of Dust 

 Pillars in the Mongolian Desert. Phenomena of Intense Heat. Hour 

 of Maximum Temperature. " Goggles " or Sand Glasses. Effects of 

 Heat and Drought in Arresting Decay. Mummies. The Egyptian 

 Embalmers' Art. Egyptian Tombs. Great " Find " of Royal Mummies 

 at Deir-El-Bahari. The preservation of Flowers, etc., in Mummy Cases. 

 Immortality of Traditions of National Glory. Mirage its Characteristic 

 Effects. The Mirage and the Waters of Oblivion. Animals not Deceived 

 by It. Loss of an Egyptian Regiment by Following Mirage. The Koran 

 on Mirage. Effects of Vast Expanse upon Perspective. Effects of 

 Atmosphere in Creating Illusions. The Desert Night. Rapid Fall of 

 Temperature after Sunset. Necessity for Warm Clothing at Night. 

 Cold Winds : their Causes and Penetrating Character. Night Marches 

 Question of Their Advisability. Count D'Escayrac de Lauture's Opin- 

 ions. The Carriage of Water. Camels and Water. Camels and Green 

 Food. Desert Watering-Places. Ancient Wells. Losses of Camels in 

 traversing Waterless Tracts. The Oases. Water Courses. The Great Al- 

 gerian Oasis of " Wargla." Beauty of the Oases. Their Generally Unhealthy 

 Climate. Artesian Weils. Flora of the Desert Zone. The Date Palm > 



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