PHYSICAL PROPERTIES. 



17 



trom the hand of the Divine Architect. A few prac- 

 tical examples will show the importance of a knowl- 

 edge of this principle, which, though taught by ob- 

 servation and even by instinct, is, nevertheless, 

 often lost sight of in the daily walks of life. 



If a carriage, horse, or boat moving with speed 

 be suddenly stopped, the passengers, riders, or any 

 loose bodies which are carried will be precipitated 

 in the direction of the motion ; because, by their in- 

 ertia, they are disposed to persevere in the motion 

 which they shared in common with that which 

 transported them. So, also, if a passenger leap 

 from a carriage in rapid motion, he will fall in the 

 direction in which the carriage is moving at the mo- 

 ment his feet touched the ground, because his body, 

 on quiting the vehicle, retains, by its inertia, the 

 motion which it had in common with it. In such a 

 case, it would be far safer to leap as far as possible 

 into the air, so that, by the time he strikes the earth, 

 the momentum of the body may have been lost ; for 

 the reason a person falls under such circumstances 

 is, that while motion is destroyed by the resistance 

 of the ground to the feet, it is retained in the upper 

 part of the body, so that the same effect is produ- 

 ced as if the feet had been tripped. In starting a 

 train of loaded cars upon a railroad, we see that a 

 considerable amount of power is neccesary to com- 

 municate motion ; but afterward, very little force 

 comparatively is required, only sufficient to over- 

 come the friction of the rails, which is slight. The 

 same holds true of loaded vehicles drawn by oxen 

 or horses. 



There can be no doubt that this property is in- 

 stinctively taught to the brute creation. For ex- 

 ample, in coursing, when the hare is closely pursued 

 by the greyhound, she suddenly doubles, that is, 

 turns back upon her course, at an oblique angle 

 with the direction in which she had been running, 

 while the hound, being much heavier, is unable to 



