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CHEMISTRY, GEOLOGY 



gas, or of a kind of air. It burns as coal-gas 

 does, but its flame is blue, and gives a very 



Fig. 2. Pig. 3. 



feeble light. Its name, from the Greek, means 

 water-maker. A candle will not burn, nor can 

 any animal live, in hydrogen gas. Mixed with 

 common air, it explodes with great violence when 

 brought into contact with flame. It is the 

 lightest of all known substances. The gas 

 burned in the streets and houses is hydrogen, 

 mixed with a peculiar kind of carbon. The ex- 

 plosions in coal-mines are caused by a mixture 

 of hydrogen and other gases with the air we 

 breathe, which are set on fire by the lamps used 



Questions. What does the name hydrogen signify? 

 What its effects on animal life ? Will it burn ? Describe 

 any other of its properties. 



