Mr. M. M. P. Muir on Chemical Notation. 9 



devise an entirely new system of notation, but only to modify 

 the existing system so as to include the new knowledge. 

 Our present notation is founded on facts ; it does not neces- 

 sarily involve any theory, only a generalization, as Dr. Wright 

 has well pointed out; hence it is not to be thrown aside 

 because at some future time it may not adequately express all 

 our knowledge. Let us wait till that knowledge is gained, 

 and then try to so modify our notation as to symbolize the 

 knowledge. 



But if we should not find it possible to do this, and it 

 becomes necessary to have a new system of notation, it will 

 be still a system which has been developed from, not a system 

 which has overthrown, the old. 



17. I have so far endeavoured to put forward reasons for 

 believing that our existing system of notation symbolizes, to 

 a certain extent, both the substances which take part in, and 

 the final products of a chemical action, and also some of the 

 relations existing between these substances and the changes 

 of energy which accompany the action. In so far as the 

 latter changes are concerned, it must, however, be confessed 

 that our ignorance is great, and that when more knowledge is 

 gained it will be necessary for us to modify our notation so as 

 to express this knowledge symbolically. 



I have sought to show that our equations represent the 

 initial and final distributions of matter during a reaction 

 symbolized, that they imply changes of energy, that in the 

 case of dissected or structural formulas we can trace a close 

 connexion between such changes of energy and the formulas, 

 and that in valency we have at any rate the rudiments of a 

 method by which the power of doing work of different sub- 

 stances may be compared. 



18. On looking at such an equation as 



Zn + H 2 S0 4 =ZnS0 4 + H 2 , 



one might imagine that the weight of zinc sulphate expressed 

 by the symbols ZnS0 4 would be at once produced on the addi- 

 tion of that quantity of sulphuric acid represented by H 2 S0 4 to 

 Zn parts by weight of zinc, and that, were a somewhat larger 

 quantity of acid to be added to the same quantity of zinc, the 

 action would not be modified. The equation appears to convey 

 this meaning ; but the meaning is erroneous. Chemical action 

 involves greater or less quantities of time ; and it is certainly 

 influenced by the total mass of the acting substances, as also 

 by the mass of the resultants, and by the relation which these 

 bear at any moment to the generating substances. 



19. Hitherto we have not been able to express such facts as 



