180 THE POPULAR SCIENCE MONTHLY 



that all that makes it significant for chemical practise is expressible 

 in this way: If any two substances unite with each other chemically, 

 they do so in such a manner that there are no particles of them so 

 small as not to follow the same law of combination that holds for the 

 substances in bulk. 



Atoms in modern chemistry are small bodies imagined to constitute 

 visible substances, and they are imagined for the purpose of incar- 

 nating, if you will, the observed trait that substances have of combining 

 with one another according to known rules. As to most of the other 

 properties of atoms, their shape, color, hardness, etc., if atoms are 

 conceived to be anything else than little particles of the substances, 

 science knows no more to-day than did Newton and Democritus. 



The purpose of this little excursion into the atomic doctrine, that 

 border-land of physical science, is to bring home something of the 

 mighty power there is in the properties of things, and in sense experi- 

 ence. It is not too much to say that the modern science of chemistry 

 was born then and there, when one property that substances have, viz.,. 

 that of definite combination with other substances, was attached to 

 the hitherto purely speculative, more or less mystical atoms of those 

 substances. 



I ask you now to recall what was said about the way we deal with 

 the salt, sodium and chlorine. Substantially the statement was that 

 we have to treat them all on exactly the same basis, so far as the process 

 of knowing is concerned. That is, we have to treat each one on the 

 basis of its own 'properties. We can not touch sodium with our 

 knowledge of the properties of chlorine, nor vice versa. Similarly, 

 we can not touch sodium with our knowledge of the properties of salt, 

 nor salt with our knowledge of the properties of sodium, except, 

 mark you, as we may say that one property of sodium is its power 

 to unite with chlorine to produce salt. My familiar expression for 

 this is that the external world and our minds are so constituted, are 

 so articulated with each other, that every object in that world must be 

 treated on its own merits. Now notice that since these substances 

 must be treated, each on its own merits, and since the sodium and 

 chlorine have the power of combining with each other in such a re- 

 markable way that they wholly lose their original properties, at least 

 temporarily, and merge into another substance, salt, with properties 

 wholly its own, we must recognize that the properties .of substances 

 manifest something of transitoriness and relativity. 



Thus are we led to the notion which I have ventured to speak of as 

 the standardization of reality. The expression is suggested by the 

 chemist's process of standardizing solutions; the process, that is, of 

 using a solution of known composition and concentration as a unit 

 of value to which to refer various reactions and processes. The mean- 

 ing is that whatever criterion of reality you apply to any natural object, 



