556 THE POPULAR SCIENCE MONTHLY. 



principles. Helmholtz, in his latest writings, fully adopts this doctrine 

 of corporeal extension. 



We thus see that there is no difficulty in reconciling extension 

 with unextended forces, and the phenomena of extension with prin- 

 ciples of action ; but this is only the first part of the problem, and it 

 becomes necessary now to ascend from these unextended forces and 

 active principles to those more or less complex manifestations which 

 make up the infinite universe, adorning space with imperishable 

 variety. Let us imagine this universe filled with the greatest conceiv- 

 able number of active principles, all identical, diffused uniformly 

 throughout immensity, and consequently in a state of perfect equi- 

 librium. All will be torpid in absolute repose, in which form without 

 shape and force without spring will be as though they were not. 

 Between a homogeneous, motionless substance, identical with itself 

 throughout space at all points, and nihility, reason perceives no dif- 

 ference. In such a system, nothing has weight, for there is no attract- 

 ing centre ; heat is no more possible for it than light, since these two 

 forms of energy are bound up with the existence of systems of unequal 

 vibrations, of diversified media, and varying molecular arrangements. 

 A fortiori, the phenomena of life will be incompatible with this uni- 

 versal unity of substance, this unchanging identity of force. 



The objective existence of things, the coming into reality of phe- 

 nomena, can only be conceived, therefore, as the work of a certain 

 number of differentiations taking place in the deep of that universal 

 energy of primal matter, which is the last result of our analysis of the 

 world. Motion, of itself alone, is enough to explain a first attribute 

 of that energy, namely, resistance, and its consequence, impenetrabil- 

 ity ; but this is only on the condition that this motion shall take place 

 in various directions. Two forces urged in opposite directions, and 

 coming to a meeting, manifestly resist each other. It is probably by 

 collisions of this sort that those variable condensations of matter, and 

 those heterogeneous groupings of which the world presents the spec- 

 tacle, have been determined. A rotary movement, communicated to 

 a mass without weight, can only engender concentric spheres, which 

 gravitate toward each other in consequence of pressure by the inter- 

 posing ether. The famous experiments of Plateau are decisive in this 

 respect. That accomplished physicist introduces oil into a mixture 

 of water and alcohol, having exactly equal density with the oil itself. 

 He inserts a metallic strip into the midst of this mass of oil, which is 

 free from the action of any force, and turns it about. The oil takes 

 the form of a sphere, and, as soon as the rotation grows very rapid, 

 breaks up, and parts into a number of smaller spheres. The celestial 

 spheres were probably formed in the same way, and an exactly similar 

 mechanical action produces those clear dew-drops, glittering like dia- 

 monds, on the leaves of plants. 



All physical phenomena, whatever their nature, are at bottom only 



