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and sunrise, also tlie lovely blue of the clear sky above 

 must not be omitted. Who can help admiring them, 

 as the crimson, golden and violet shades blend hand- 

 somely together and become ever deeper and more lus- 

 trous as the great sun approaches or departs, and the 

 sky appears as if set with gems and rubies in rich pro- 

 fusion, and glitters as if covered with innumerable 

 crystals. The cause of these tints is based upon the 

 dispersion of the sun's rays in passing through tl^e 

 clouds and vapor, causing those colors to show which 

 are least turned out of their course. The azure blue 

 of our sky is supposed to be caused by the reflection of 

 light from numerous small opaque particles which are 

 in the air, all of these having a tendency to produce a 

 bluish cast. To look at the sky when clear a person 

 would naturally think that scarcely anything could be 

 purer, but this beautiful appearance is formed by the 

 refraction of light from minute dust particles which 

 fill the atmosphere; also other substances. The atmos- 

 phere is wonderful; it is a vast ocean of air which 

 would be the same depth everywhere, except for the 

 earth's rotation and the heat of the sun. Owing to 

 these causes the upper regions are thrown in huge 

 masses in some places, while it is deeply hollowed out 

 in others, thus making a constant circulation and in- 

 terchange between the poles. By retaining and modi- 

 fying the solar heat, absorbing moisture and distribut- 

 ing it over the earth, and supplying animals and plants 

 with the life-giving oxygen. The atmosphere fills a 

 highly important station in the economy of the globe. 

 Meteorology is the science v/hich treats upon it in all 

 its forms and changes. The elasticity of the atmos- 



