364 Mr. Faraday [Feb. 27, 



heat, or electricity, or gravitation, or any other form of force, 

 ■which either wittingly or unwittingly dispenses with the principle 

 of conservation, is more liable to the charge, than those which, by 

 including it, become so far more strict and precise. 



Supposing that the truth of the principle of the conserva- 

 tion of force is assented to, I come to its uses. No hypothesis 

 should be admitted nor any assertion of a fact credited, that 

 denies the principle. No view should be inconsistent or incompati- 

 ble with it. Many of our hypotheses in the present state of 

 science may not comprehend it, and may be unable to suggest its 

 consequences ; but none should oppose or contradict it. 



If the principle be admitted, we perceive at once, that a theory 

 or definition, though it may not contradict the principle cannot be 

 accepted as sufficient or complete unless the former be contained 

 in it ; that however well or perfectly the definition may include 

 and represent the state of things commonly considered under it, 

 that state or result is only partial, and must not be accepted as 

 exhausting the power or being the full equivalent, and therefore 

 cannot be considered as representing its whole nature; that, 

 indeed, it may express only a very small part of the whole, only a 

 residual phenomenon, and hence give us but little indication of the 

 full natural truth. Allowing the principle its force, we ought, in 

 every hypothesis, either to account for its consequences by saying 

 what the changes are when force of a given kind apparently dis- 

 appears, as when ice thaws, or else should leave space for the idea of 

 the conversion. If any hypothesis, more or less trustworthy on other 

 accounts, is insufficient in expressing it or incompatible with it, the 

 place of deficiency or opposition should be marked as the most 

 important for examination ; for there lies the hope of a discovery of 

 new laws or a new condition of force. The deficiency should never 

 be accepted as satisfactory, but be remembered and used as a 

 stimulant to further inquiry ; for conversions of force may here be 

 hoped for. Suppositions may be accepted for the time, provided 

 they are not in contradiction with the principle. Even an increased 

 or diminished capacity is better than nothing at all ; because such 

 a supposition, if made, must be consistent with the nature of the 

 original hypothesis, and may, therefore, by the application of 

 exp.eriment, be converted into a further test of probable truth. 

 The case of a force simply removed or suspended, without a trans- 

 ferred exertion in some other direction, appears to me to be 

 absolutely impossible. 



If the principle be accepted as true, we have a right to pursue it 

 to its consequences, no matter what they may be. It is, indeed, a 

 duty to do so. A theory may be perfection, as far as it goes, but 

 a consideration going beyond it, is not for that reason to be shut 

 out. We might as well accept our limited horizon as the limits of 

 the world. No magnitude, either of the phenomena or of the 

 results to be dealt with, should stop our exertions to ascertain, by 



