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visible from the same cause. Weary travelers upon 

 the desert are in some cases sadly disappointed at not 

 finding the beautiful islands, refreshing streams, and 

 trees which he saw in the above named manner. The 

 only place which cheers the desert company is the oasis 

 — a small spot or tract of ground wdiich is always fer- 

 tile. 



Halos and Coronel are rings of prismatic colors sur- 

 rounding the sun and moon. They are caused by the 

 presence in the air of small crystals of ice or snow. 

 Parhelia or mock suns and Paraselense or mock moons 

 are seen when the complicated circles intersect each 

 other. Here bright spots are seen which somewhat 

 resemble the sun and moon. Coronae are similar cir- 

 cles seen around the moon, and are caused by small 

 quantities of condensed vapor in the air. They gen- 

 erally indicate changes in the weather. Many and 

 varied are the natural displays which are witnessed 

 over all parts of the world, and when describing one it 

 brings to viev/ vividly a large number of them. 



Another of importance, though not seen in bright 

 colors or figures is the effect produced by the attraction 

 of the sun and moon upon bodies of water, causing 

 high and low tides. If the earth did not revolve the 

 tidal waves would in reality follow the moon in its rev- 

 olution around the earth. When the sun and moon 

 act together on the same hemisphere the wave is high- 

 er than usual and is then called spring tides. These 

 two bodies or plannets have great influence over the 

 water, and are the main agencies of its changes. 



While treating upon the beautiful objects seen in 

 the world, the gorgeous hues and tints of the sunset 



