THE EEASON WHY. 



" Behold there arisjeth a little cloud from the sea, of the bigness of a man's 



hand. And it came to pass in the meantime, that the heaven was black 



with clouds and wind, and there was a great rain." 1 KINGS xviu. 



Because water is highly expansive, and rises in thin vapour, 

 when in contact with warm and dry air. 



750. Why does steam issue from the spout of a kettle ? 

 Because the heat of the fire passes into the water, and drives 



its atoms apart, making- those of them that rise quickly to 

 the surface lighter than the air, upon which they consequently 

 rise. 



751. Why does water become solid -when it freezes ? 



Because the latent heat of the water passes away from be- 

 tween its atoms into the air ; the acorns, therefore, draw closer 

 together. 



752. Why, if the atoms of water draw closer together when 

 freezing, does ice expand, and occupy greater space than 

 water ? 



Because, when the atoms of water are congealing, they do not 

 form a compact mass, but arrange themselves in groups of crystal 

 points, which occupy greater space. Water contracts when 

 freezing until it sinks to 40 deg., and then it expands as ice is 

 formed. 



32 deg. is said to be the freezing point, but it should be called the frozen 

 point. 



753. Wliy does water boil ? 



Because heat, entering into the lower portions of the water, 

 expands it ; the heated portions are then specifically lighter than 

 those that are cooler ; the hot water therefore rises upward, and 

 forces the cooler water down. 



754. What proportion of the earth's surface is covered 

 with water ? 



There are about one hundred and forty seven millions of square 

 miles of water, to forty -nine and a half millions of square miles of 

 land. 



755. What is the amount of water pressure ? $ . 



The pressure of the sea, at the depth of 1,100 yards, is equal to 

 15,000 Ibs. to the square inch. 

 8 



