40 THE NATUEE AND ORIGIN OF LIFE 



with which it comes into relations capable of being expressed 

 in a simple formula. In particular, we should understand 

 the advantage there is in studying the struggle of phenomena 

 with other phenomena of the same dimension as themselves 

 for example, of living bodies which are colloids with other 

 colloid bodies living or not-living. 



The Method of Approximate Laws in Physics 



Though quite the opposite of that genuinely natural 

 method of investigation which consists in the search after 

 simple laws, the method of Approximate Laws is also of 

 undoubted use in many cases. Its theoretic model is Helm- 

 holtz's Resonators, by which phenomena complex from the 

 human point of view are decomposed into several other 

 phenomena whose superposition reproduces the first, while 

 each of them, taken separately, is susceptible of scientific 

 analysis. 



Suppose we draw a violin bow across a brass wire so 

 stretched that it vibrates its whole length and produces what 

 is called a simple sound. A similar wire, but this time of 

 silver, would give the same sound in the same conditions. 

 And yet the two sounds would differ by a special quality 

 their timbre. 



To assert the identity of such sounds is to lay down an 

 Approximate Law. The two sounds may be identical in 

 pitch and in amplitude, and yet we distinguish one from 

 the other because they have not the same timbre. 



Helmholtz's method applied to the two cases enables 

 us to discover that the fundamental sound in each is accom- 

 panied by different harmonics. But suppose we did not 

 know how to use the resonators we should be forced 

 to assert that we had discovered an Approximate Law. 



We do the same thing for a stone falling into a well. 



