SCIENCE OF COMMON THINGS. 



All bodies attract each other. Feather and the earth. 



76 How long witt smoke continue to float above the surface of the earth f 



Until its particles, uniting, become heavier than the 

 air, when they descend in the form of small flakes of 

 soot. 



77 Why do bubbles in a cup of tea range round the sides of the cup ? 



Because the cup attracts them. 



78 Why do att the little bubbles tend towards the large ones f 



^ Because the large bubbles (being the superior masses) 

 attract them. 



79 Why do the bubbles of a cup of tea follow a tea-spoon f 



Because the tea-spoon attracts them. 



SO Do all bodies attract each other equally f 



They attract each other with forces proportioned to 

 their masses. 



8 1 A feather falls to the ground by the influence of the earth's attraction. 

 Now, as all bodies attract each other, does the feather attract or draw up the 

 earth in any degree towards itself? 



It does, with a force proportioned to its m-ass / but 

 as the mass of the earth is infinitely greater than the 

 feather, the influence of the feather is infinitely small, 

 and we are unable to perceive it. 



83 What would be the consequence if the feather did not attract the 

 earth f 



If any portion of the earth, however small, failed to 

 attract another portion, and not be itself attracted, the 

 axis of the earth would le immediately changed, involv- 

 ing an alteration of climate, and the place of the ocean 

 in its bed. 



83 Why is it more dangerous to fall from, a lofty elevation than from a 

 low one ? 



As the attraction of the earth varies inversely with 

 the square of the distance, the force with which a fall- 

 ing body will strike the ground will increase in propor- 

 tion to the height from which it has fallen. 



84 In what direction does a body, when not supported, endeavor to fall ? 



In a line drawn from its centre of gravity towards 

 the centre of the earth. 



85 Is the attraction of the earth the same at att distances from its sur- 

 face or centre f 



