232 COSMICAL ARRANGEMENTS. 



conceptions. We conceive that this is an er- 

 roneous view, and that these laws are known to 

 us to be what they are, by experience only ; 

 that the laws of motion might, so far as we can 

 discern, have been any others. They appear 

 therefore to be selected for their fitness to answer 

 their purposes ; and we may, perhaps, be able to 

 point out some instances in which this fitness is 

 apparent to us. 



Newton, and many English philosophers, teach 

 the existence of three separate fundamental laws 

 of motion, while most of the eminent mathe- 

 maticians of France reduce these to two, the law 

 of inertia and the law that force is proportional to 

 velocity. As an example of the views which we 

 wish to illustrate, we may take the law of inertia, 

 which is identical with Newton's first Law of 

 Motion. This law asserts, that a body at rest 

 continues at rest, and that a body in motion 

 goes on moving with its velocity and direction 

 unchanged, except so far as it is acted on by 

 extraneous forces.* 



We conceive that this law, simple and univer- 

 sal as it is, cannot be shown to be necessarily 



* If the Laws of Motion are stated as three, which we conceive 

 to be the true view of the subject, the other two, as applied in 

 mechanical reasonings, are the following : 



Second Law. When a force acts on a body in motion, it pro- 

 duces the same effect as if the same force acted on a body at rest. 



Third Law. When a force of the nature of pressure produces 

 motion, the velocity produced is proportional to the force, other 

 things being equal. 



