38 MATTER AND FORCE, IN PHYSICAL PHENOMENA. 



matter are the sole exponents of what we call forces, 

 we still cannot annul the notion of power, other than the 

 matter itself, as initiating and evolving these actions. 

 Eefine upon the atomic theory to the uttermost, and 

 show the mutual convertibility of forces by the different 

 material media through which they act high achieve- 

 ments these of our own time the question still presses 

 upon us, How are initiated, how maintained, these 

 various and unceasing motions of matter, in masses or 

 molecules, lifeless or organised into life ? Would they 

 not, if depending solely on causes intrinsic to matter 

 itself, neutralise each other in process of time, and sub- 

 side into absolute repose ? Must we not thenJook 

 to some cause of action from without some power or 

 powers to which no material attributes can be assigned, 

 and which may possibly operate in other effects, not 

 yet grasped by human observation ? 



It is hardly possible to deal with this subject other- 

 wise than interrogatively. Take heat, for example a 

 power familiar in one form or other to every moment 

 of our existence, arid closely connected with the mole- 

 cular theory, both by thermometric conditions and 

 by the more obscure conditions of radiant, specific, and 

 latent heat. If, in compliance with modern views, we 

 regard heat as one mode of motion of matter, we come 

 upon the question, whence originated the movements, 

 propagated thus endlessly, in every form and degree, 

 by and through the atoms or molecules of the material 

 world ? Is it a condition native to, and embodied in, 

 matter, and expressed to our senses and instruments 

 in the various acts by which calorific equilibrium is 



