150 THE ANATOMY OF SCIENCE 



ever picks up a bridge hand with thirteen 

 trumps you will probably tell it to all your 

 friends, and, indeed, such a hand is a very rare 

 fluctuation from the general run of nondescript 

 hands. 



There is a psychological element in all this. 

 If we look down from a window upon a street of 

 New York and see the people emerging from a 

 subway exit, some occurrence may draw our 

 attention to one group of ten people. We make 

 note of their faces and their clothes. They thus 

 become in some measure familiar to us, and it 

 strikes us as remarkable that these ten people 

 are about to melt into the crowds of the great 

 city and will never again meet together. Yet all 

 through the day each will be one of a group 

 which differs from the first only in that we have 

 not become acquainted with its members. 



Since the rules of chance arrangements con- 

 tain every essential feature of the second law 

 of thermodynamics, let me illustrate it further 

 by this apparatus (Figure 24), in which I have 

 one tube containing ten black balls and one 

 tube containing ten white balls. ^ If I invert the 



5 For this illustration and several references in this lec- 

 ture I am indebted to the interesting book of C. E. Guye> 

 Physico-Chemical Evolution, 



