716 SCIENCE AND HYPOTHESIS 



and obey the known laws of dynamics. But the elements are extremely 

 numerous, and become blended more and more, so that to our crude 

 sight all appears to tend towards uniformity i.e., all seems to 

 progress in the same direction, and that without hope of return. The 

 apparent irreversibility is therefore but an effect of the law of great 

 numbers. Only a being of infinitely subtle senses, such as Maxwell's 

 demon, could unravel this tangled skein and turn back the course of 

 the universe. 



This conception, which is connected with the kinetic theory of 

 gases, has cost great effort and has not, on the whole, been fruitful; 

 it may become so. This is not the place to examine if it leads to con- 

 tradictions, and if it is in conformity with the true nature of things. 



Let us notice, however, the original ideas of M. Gouy on the Brown- 

 ian movement. According to this scientist, this singular movement 

 does not obey Carnot's principle. The particles which it sets moving 

 would be smaller than the meshes of that tightly drawn net; they 

 would thus be ready to separate them, and thereby to set back the 

 course of the universe. One can almost see Maxwell's demon at work. 1 



To resume, phenomena long known are gradually being better clas- 

 sified, but new phenomena come to claim their place, and most of 

 them, like the Zeeman effect, find it at once. Then we have the 

 cathode rays, the X-rays, uranium and radium rays; in fact, a whole 

 world of which none had suspected the existence. How many unex- 

 pected guests to find a place for! No one can yet predict the place 

 they will occupy, but I do not believe they will destroy the general 

 unity; I think that they will rather complete it. On the one hand, 

 indeed, the new radiations seem to be connected with the phenomena 

 of luminosity; not only do they excite fluorescence, but they some- 

 times come into existence under the same conditions as that property ; 

 neither are they unrelated to the cause which produces the electric 

 spark under the action of ultra-violet light. Finally, and most im- 

 portant of all, it is believed that in all these phenomena there exist 

 ions, animated, it is true, with velocities far greater than those of 

 electrolytes. All this is very vague, but it will all become clearer. 



Phosphorescence and the action of light on the spark were regions 

 rather isolated, and consequently somewhat neglected by investigators. 

 It is to be hoped that a new path will now be made which will facili- 

 tate their communications with the rest of science. Not only do we 

 discover new phenomena, but those we think we know are revealed in 

 unlooked-for aspects. In the free ether the laws preserve their majes- 

 tic simplicity, but matter properly so called seems more and more 



i Clerk-Maxwell imagined some supernatural agency at work, sorting mole- 

 cules in a gas of uniform temperature into (a) those possessing kinetic en- 

 ergy above the average, (6) those possessing kinetic energy below the average. 



-[TB.] 



