HOW PHENOMENA ARE INTERPRETED. 71 



more mysterious than an exchange of motion ; there is no 

 imponderable substance to be now in and now out, only a 

 change in the conditions. Taking this view of heat it is easy 

 to see that the terminology served to mislead thinking ; but the 

 view here presented shows that heat cannot be properly 

 called a force any more than the vibrations of a bell or a piano 

 string can be called a force, and so heat is out of the category 

 of force. 



Light was also an imponderable substance. Now we know 

 it to be wave motion in the ether, and the vibrations that con- 

 stitute the heat of molecules set up these waves in the ether, 

 and the latter conducts them away at the high rate of 186,000 

 miles a second. The heat motions are the antecedents of the 

 light motions in the ether in every case, and every ray of light 

 when traced back to its source ends in a vibrating molecule. 

 So if heat be not a force, neither can light be so considered, 

 and two of the imponderables are gone as forces. 



Electricity as another wonderful force is known to originate 

 in the motions of molecules, for both by chemical action and 

 by heat action it is produced. It also disappears when allowed 

 to do either chemical, thermal, or mechanical work. As it has 

 molecular motion for its antecedent and molecular work for 

 its resultant, it follows that its nature cannot be materially 

 different from that of the others. Indeed, so well established 

 are these interrelations between heat and electricity that large 

 industrial enterprises are founded upon them. The point here 

 is that electricity, as an independent something, a force that 

 may be summoned like an Afrite in The Arabian Nights to do 

 duty for a while and then be dismissed from service to be no 

 one knows where, is an idea wholly wrong. It is a condition, 

 not a thing, for electrical energy may be wholly transformed 

 into heat energy or into light or other kinds of work. So far 

 we have only matter and forms of motion in matter, and forces 

 as such have no existence. And if this be true it will be well 

 to abandon the notion of either of these agencies as forces or 

 things having an existence apart from matter. There is no 

 evidence for such a view, and any quantity of evidence against 

 it. The explanation of the phenomena due to either or all of 



