176 THE SEASON WHY. 



'Where wast thouwhen I laid the foundations of the earth? declare, if 

 hast understanding. 



relative to that of the air, the medium through which the feather 

 and the shilling pass. If there were no air, a shilling and a feather 

 dropped at the same time from a height of forty miles, would reack 

 the earth at the same moment. 



CHAPTER XXXVII. 



792. What is repulsion ? 



Kepulsion is that property in matter by which it repels or recedes 

 from, those bodies for which it has no attraction or affinity. 



793. Why does dew form into round drops upon the leaves 

 of plants ? 



Because it repels the air, and the substances of the leaves upon 

 which it rests. Because, also, its own particles cohere. 



794. Why do drops of water roll over dusty surfaces ? 

 Because they repel the particles of dust ; and also because their 



own particles have a stronger attraction for each other than for 

 the particles of dust. 



795. Why does a needle float when carefully laid upon the 

 siirface of water ? 



Because the needle and the water mutually repel each other. 



796. Why does water, when dropped upon hot iron, move 

 about in agitated globules ? 



Because the caloric repels the particles of the water. 



797. Why does oil float upon the surface of water ? 

 Because, besides being specially lighter than water, the particles 



of the oil and the water mutually repel each other. 



798. What is carbonic acid? 



Carbonic acid is a mixture of carbon and oxygen, in tba 

 proportion of 3 Ibs. of carbon to 8 Ibs. of oxygen. 



799. Where does carbonic acid cliiefty exist t 



