1857.] On the Conservation of Force. 457 



science, which consists in the enunciation of problems to be 

 solved. It will lead us, in any case where the force remaining 

 unchanged in form is altered in direction only, to look for the 

 new disposition of the force ; as in the cases of magnetism, 

 static electricity, and perhaps gravity, and to ascertain that, as 

 a whole, it remains unchanged in amount : or, if the original 

 force disappear, either altogether or in part, it will lead us to 

 look for the new condition or form of force which should result, 

 and to develope its equivalency to the force that has disappeared. 

 Likewise, when force is developed, it will cause us to consider 

 the previously existing equivalent to the force so appearing ; 

 and many such cases there are in chemical action. When 

 force disappears, as in the electric or magnetic induction after 

 more or less discharge, or that of gravity with an increasing 

 distance, it will suggest a research as to whether the equivalent 

 change is one within the apparently acting bodies, or one ex- 

 ternal (in part) to them. It will also raise up inquiry as to the 

 nature of the internal or external state, both before the change 

 and after. If supposed to be external, it will suggest the 

 necessity of a physical process, by which the power is com- 

 municated from body to body ; and in the case of external 

 action, will lead to the inquiry, whether, in any case, there can 

 be truly action at a distance, or whether the ether, or some 

 other medium, is not necessarily present. 



We are not permitted as yet to see the nature of the source 

 of physical power, but we are allowed to see much of the con- 

 sistency existing amongst the various forms in which it is pre- 

 sented to us. Thus if, in static electricity, we consider an act 

 of induction, we can perceive the consistency of all other like 

 acts of induction with it. If we then take an electric current, 

 and compare it with this inductive effect, we see their relation 

 and consistency. In the same manner we have arrived at a 

 knowledge of the consistency of magnetism with electricity ; 

 and also of chemical action and of heat with all the former ; 

 and if we see not the consistency between gravitation with any 

 of these forms of force, I am strongly of the mind that it is 

 because of our ignorance only. How imperfect would our idea 

 of an electric current now be, if we were to leave out of sight 

 its origin, its state and dynamic induction, its magnetic influ- 

 ence, its chemical and heating effects ! or our idea of any one 



