380 THE CONSERVATION OF FOKCE. 



forces must De equally unchangeable. Or, there may be but 

 one cause for these three sets of actions, and in place of three 

 forces we may really have but one, convertible in its manifes- 

 tations ; then the proportions between one set of actions and 

 another, as the chemical and the electrical, may become very 

 variable, so as to be utterly inconsistent with the idea of the 

 conservation of two separate forces (the electrical and 

 the. chemical), but perfectly consistent with the conservation 

 of a force, being the common cause of the two or more sets 

 of action. 



It is perfectly true that we cannot always trace a force by 

 its actions, though we admit its conservation. Oxygen and 

 hydrogen may remain mixed for years without showing any 

 signs of chemical activity ; they may be made at any given 

 instant to exhibit active results, and then assume a new 

 state, in which again they appear as passive bodies. Now, 

 though we cannot clearly explain what the chemical force is 

 doing, that is to say, what are its effects during the three 

 periods before, at, and after the active combination, 1 and only 

 by very vague assumption can approach to a feeble concep- 

 tion of its respective states, yet we do not suppose the creation 

 of a new portion of force for the active moment of time, or 

 the less believe that the forces belonging to the oxygen and 

 hydrogen exist unchanged in their amount at all these periods, 

 though varying in their results. A part may at the active 

 moment be thrown off as mechanical force, a part as radiant 

 force, a part disposed of we know not how ; but believing, by 

 the principle of conservation, that it is not increased or 

 destroyed, our thoughts are directed to search out what 

 at all and every period it is doing, and how it is to be 

 recognized and measured. A problem, founded on the 

 physical truth of nature, is stated, and, being stated, is on the 

 way to its solution. 



Those who admit the possibility of the common origin of 

 all physical force, and also acknowledge the principle of con- 



