10 Dr. E. J. Mills on the First Principles of Chemistry. 



I cannot dismiss the question of chemical substances without 

 referring for a moment to those that are isomeric. The general 

 phenomena of isomerism are conceived to point irresistibly to 

 an atomic theory of some kind. As I have discussed this topic 

 elsewhere*, and shown that all the experimental evidence on 

 this subject leads up to continuity, I will not again refer to it, 

 but merely adduce the following simple illustration of my view. 

 Imagine a number of insulated Leyden jars, alike in weight, 

 volume, and every other particular of construction. Let each 

 of these be charged with a different amount of electricity ; and 

 let the electricity be positive in some jars, in others negative. 

 Now let the same piece of charged gold-leaf be caused to ap- 

 proach the knob of each jar in succession, its initial state being 

 restored before each approach : in no two cases will the attrac- 

 tion (or repulsion) be the same in amount. This is exactly 

 the position of the phenomenon of isomerism. All we know 

 of it is that certain bodies, having equal (gaseous) volumes for 

 equal weights, behave differently when a standard energy is 

 applied to them. To measure, both in quality and quantity, 

 the energy associated with each isomeric substance, is to give 

 a complete account of the phenomenon of isomerism. Into 

 this account the atomic element does not enter. 



Thus, then, whether we consider the act of mechanical di- 

 vision or of chemical decomposition, or the fundamental idea 

 educible from the classification of chemical substances, or what 

 is the most real meaning of our sensations, the answer is prac- 

 tically a single one. The substances that take part in chemical 

 actions have no parts or radicals ; they are homogeneous, con- 

 sisting of directed motion. 



Energy is only known to us as diffuse (non-isolable) motion ; 

 matter, as concrete (isolable) motion. Whether the one kind 

 can be transformed into the other, and what, in case such a 

 change can be effected, is the nature of the intermediate sub- 

 stances, are questions which I can only raise, and not solve. 

 Until periodic verifications are made of the quantities in which 

 standard elements combine, we have not even approached the 

 threshold of an experimental answer. No one, for example, 

 can assert that argentic chloride has the same composition now 

 that it had 100 years ago. So uncertain is the axiom that no 

 matter can ever be lost. 



(9) Some consequences of this result must now be traced. 



(a) The vices and virtues of the common chemical equations 

 are typically depicted in the well-known expression 



2H 2 + 2 = 2H 2 0. 



* Laboratory, 1867, p. 54. 



