270 Mr. M. M. Pattison Muir on Chemical Classification. 



functions of this Tariable. A further and more careful study 

 of the exact properties of groups of compounds and of ele- 

 ments will doubtless enable us to make a nearer approximation 

 to the nature of the function in question. Supposing that 

 the periodic law be clearly established, we shall then be 

 met with such questions as these : — Are there periods within 

 periods ? Is the divergence froni the law itself periodic ? 

 and so on. The field for inquiry is evidently immense. 

 Very many measurements must be made before we can 

 attempt an answer to the simplest of the questions presenting 

 themselves for solution. 



It would not be difficult, perhaps, even now, to deduce some 

 empirical mathematical expression which should appear to 

 satisfy some of the results concerning the connexion of 

 atomic w^eight and physical properties. If the measurements 

 be accurate, such an empirical law may be generally easily 

 enough deduced ; but in a case so complicated as that pre- 

 sented to the chemist, an empirical law would be of little 

 value ; it would almost certainly be untrue. We must be 

 content to wait for further researches, in the hope of being 

 one day able to deduce a rational law which shall cover all 

 the facts, and shall enable us to express, with a fair degree of 

 accuracy, the nature of the function of which the chemical 

 and physical properties of elements and compounds, and the 

 atomic weights of the elements, are values. 



In any attempts which may be made to solve this problem, 

 it will be necessary to remember that most minds are biased 

 in favour of a simple law, that we are ready to believe that 

 Nature must be extremely simple in her worhing, whereas the 

 facts which we certainly know all point to the extreme com- 

 plexity of Nature's laws. Each more exact investigation 

 shows that w^hat we had before accepted as a full expression 

 of the facts is but an approximatioli to such an expression. 

 We are really dealing, as Prof. Jevons remarks, with pheno- 

 mena made up of an infinite number of infinitely small units. 

 It is only our incompetency to solve Nature's problems 

 w^hich obliges us continually to assume the phenomena to be 

 much more simple than they really are. 



It seems to me that a consideration of the infinity of the 

 subject presented to the naturalist should prevent many of 

 those unseemly controversies concerning pet theories which 

 now and again disgrace the pages of works pretending to be 

 devoted to an investigation of Nature. 



Chemists are not wholly free from blame for the manner in 

 which they incline to allow theories to usurp the place of 



