THE VALUE OF SCIENCE 339 



square of the distance, and this attraction is the sole force which influ- 

 ences their movements. But if our senses were sufficiently keen to 

 show us all the details of the bodies which the physicist studies, the 

 spectacle thus disclosed would scarcely differ from the one the astrono- 

 mer contemplates. There also we should see material points, sepa- 

 rated from one another by intervals, enormous in comparison with 

 their dimensions, and describing orbits according to regular laws. 

 These infinitesimal stars are the atoms. Like the stars proper, they 

 attract or repel each other, and this attraction or this repulsion fol- 

 lowing the straight line which joins them, depends only on the dis- 

 tance. The law according to which this force varies as function of 

 the distance is perhaps not the law of Newton, but it is an analogous 

 law ; in place of the exponent — 2, we have probably a different expo- 

 nent, and it is from this change of exponent that arises all the diver- 

 sity of physical phenomena, the variety of qualities and of sensations, 

 all the world, colored and sonorous, which surrounds us; in a word, 

 all nature. 



Such is the primitive conception in all its purity. It only remains 

 to seek in the different cases what value should be given to this expo- 

 nent in order to explain all the facts. It is on this model that Laplace, 

 for example, constructed his beautiful theory of capillarity; he regards 

 it only as a particular case of attraction, or, as he says, of universal 

 gravitation, and no one is astonished to find it in the middle of one 

 of the five volumes of the ' Mecanique celeste.' More recently Briot 

 believes he penetrated the final secret of optics in demonstrating that 

 the atoms of ether attract each other in the inverse ratio of the sixth 

 power of the distance ; and Maxwell, Maxwell himself, does he not say 

 somewhere that the atoms of gases repel each other in the inverse ratio 

 of the fifth power of the distance ? We have the exponent — 6, or 

 — 5, in place of the exponent — 2, but it is always an exponent. 



Among the theories of this epoch, one alone is an exception, that 

 of Fourier; in it are indeed atoms acting at a distance one upon the 

 other; they mutually transmit heat, but they do not attract, they 

 never budge. From this point of view, Fourier's theory must have 

 appeared to the eyes of his contemporaries, to those of Fourier him- 

 self, as imperfect and provisional. 



This conception was not without grandeur; it was seductive, and 

 many among us have not finally renounced it ; they know that one will 

 attain the ultimate elements of things only by patiently disentangling 

 the complicated skein that our senses give us; that it is necessary to 

 advance step by step, neglecting no intermediary; that our fathers 

 were wrong in wishing to skip stations; but they believe that when 

 one shall have arrived at these ultimate elements, there again will be 

 found the majestic simplicity of celestial mechanics. 



