Heat 



in 



FIG. 54. Will boiling water get hotter if you make it boil harder? 



that many people do not know ; and their gas bills 

 would be much smaller if they knew it. Try this ex- 

 periment : 



Experiment 38. Heat some water to boiling. Put the 

 boiling-point thermometer into the water (the thermom- 

 eter graduated to 110 Centigrade and 220 Fahrenheit), 

 and note the temperature of the boiling water. Turn up 

 the gas and make the water boil as violently as possible. 

 Read the thermometer. Does the water become appre- 

 ciably hotter over the very hot fire than it does over the 

 low fire, if it is boiling in both cases? But in which case 

 is more steam given off? Will a very hot fire make the 

 water boil away more rapidly than a low fire? 



