CHAPTEK XXIII. 



STORED ENERGY IN WATER. 



In our last chapter we traced the upward 

 movement in the mercury of the thermometer 

 from 10 degrees below the freezing point up to 

 the boiling point of water. We found that the 

 thermometer was arrested at 32 degrees and 

 remained stationary at that point until all the 

 ice was melted, notwithstanding the fact that 

 heat was being constantly applied. After the 

 ice is all melted the mercury moves upward 

 until it reaches the boiling point of water, 

 where the movement is again arrested, and al- 

 though the heat is being continuously applied, 

 it remains stationary until all the water is 

 evaporated. If we push the process still fur- 

 ther, with a sufficient -application of energy we 

 can separate the vapor molecules into their 

 original elements, oxygen and hydrogen. 



Let us go back now to the freezing point of 

 water and see what is becoming of the heat 

 that is consumed in melting the cake of ice, 

 and still does not produce any effect upon the 

 mercury in the thermometer. Sensible heat, 



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