744 The Outline of Science 



and the hydrogen gas as the issue. And his accounts balanced. 

 Nowadays we are so sure that the accounts must balance, that if 

 they do not, then we must discredit the experiment. The solid ice 

 becomes running water, which is caught up into the air as mist, 

 which may become rain on the cold surface of the mountains; but, 

 in all the protean changes, there is neither creation nor destruction. 

 We can neither create nor destroy the smallest particle; the 

 elements which enter into the composition of the soap-bubble film 

 are as lasting as those which form the granite rocks. Nothing can 

 go lost, that is certain ! 



At the entrance of a great Exhibition there is usually a 

 change-office, which is the seat of busy operations throughout the 

 day. Sometimes a visitor comes with a one pound note, which is 

 not acceptable at the turnstile, and asks for "small money"; some- 

 times a tramway-conductor comes with 120 pennies, and begs for 

 something lighter; and there are all sorts of operations. But if 

 the change-office is fortunate enough to have perfectly accurate 

 operators, it will not make anything or lose anything all the live- 

 long day. The form of the money is continually changing, but 

 the amount of the money remains always the same. So must it be 

 in all chemical operations. There cannot be anything massive or 

 quantitative in the end which was not there in the beginning, nor 

 anything in the beginning which has not its precise quantitative 

 counterpart in the end. How, then, can we think of the chemist 

 as creative? 



Constancy in the Properties of Elements 



But we must go a step further. There is a remarkable 

 stability in the properties of things. There are chemical elements 

 in unthinkably distant stars, so the spectroscope tells us, which 

 are the same as those on our own earth. Moreover, as the spectro- 

 scope continues to tell us, the properties of these elements remain 

 the same, whether here or there. A molecule of hydrogen in the 

 dog-star Sirius seems to behave just like a molecule of hydrogen 



