440 POPULAR SCIENCE MONTHLY 



ring formed of a very great number of very small negative electrons. 

 Such is the planet Saturn with its rings. This is a very interest- 

 ing attempt, but not yet wholly satisfactory; this attempt should be 

 renewed. We will penetrate, so to speak, into the inmost recess of 

 matter. And from the particular point of view which we to-day 

 occupy, when we know why the vibrations of incandescent bodies differ 

 thus from ordinary elastic vibrations, why the electrons do not behave 

 like the matter which is familiar to us, we shall better comprehend the 

 dynamics of electrons and it will be perhaps more easy for us to 

 reconcile it with the principles. 



Conventions Preceding Experiment. — Suppose, now, that all these 

 efforts fail, and, after all, I do not believe they will, what must be 

 done? Will it be necessary to seek to mend the broken principles by 

 giving what we French call a coup de pouce f That evidently is always 

 possible, and I retract nothing of what I have said above. 



Have you not written, you might say if you wished to seek a quarrel 

 with me — have you not written that the principles, though of experi- 

 mental origin, are now unassailable by experiment because they have 

 become conventions? And now you have just told us that the most 

 recent conquests of experiment put these principles in danger. 



Well, formerly I was right and to-day I am not wrong. Formerly 

 I was right, and what is now happening is a new proof of it. Take, 

 for example, the calorimetric experiment of Curie on radium. Is it 

 possible to reconcile it with the principle of the conservation of energy ? 

 This has been attempted in many ways; but there is among them 

 one I should like you to notice; this is not the explanation which 

 tends to-day to prevail, but it is one of those which have been pro- 

 posed. It has been conjectured that radium was only an intermediary, 

 that it only stored radiations of unknown nature which flashed through 

 space in every direction, traversing all bodies, save radium, without 

 being altered by this passage and without exercising any action upon 

 them. Radium alone took from them a little of their energy and 

 afterward gave it out to us in various forms. 



What an advantageous explanation, and how convenient ! First, 

 it is unverifiable and thus irrefutable. Then again it will serve to 

 account for any derogation whatever to Mayer's principle; it answers 

 in advance not only the objection of Curie, but all the objections that 

 future experimenters might accumulate. This new and unknown 

 energy would serve for everything. 



This is just what I said, and therewith we are shown that our 

 principle is unassailable by experiment. 



But then, what have we gained by this stroke? The principle is 

 intact, but thenceforth of what use is it? It enabled us to foresee 

 that in such or such circumstance we could count on such a total 



