i8o CORRELATION OF PHYSICAL FORCES. 



whenever it is affected by these forces. I believe he will 

 seldom do this in vain. It was not until I had long reflected 

 on the subject that I ventured to publish my views ; their 

 publication may induce others to think on their subject- 

 matter. They are not put forward with the same objects, nor 

 do they aim at the same elaboration of detail, as memoirs on 

 newly-discovered physical facts : they purport to be a method 

 of mentally regarding known facts, some few of which I have 

 myself made known on other occasions, but the great mass of 

 which have been accumulated by the labours of others, and 

 are admitted as established truths. Everyone has a right to 

 view these facts through any medium he thinks fit to employ, 

 but some theory must exist in the minds of those who reflect 

 upon the many new phenomena which have recently, and more 

 particularly during the present century, been discovered. It 

 is by a generalised or connected view of past acquisitions in 

 natural knowledge that deductions can best be drawn as to 

 the probable character of the results to be anticipated. It is 

 a great assistance in such investigations to be intimately con- 

 vinced that no physical phenomenon can stand alone : each is 

 inevitably connected with anterior changes, and as inevitably 

 productive of consequential changes, each with the other, and 

 all with time and space ; and, either in tracing back these 

 antecedents or following up their consequents, many new 

 phenomena will be discovered, and many existing phenomena 

 hitherto believed distinct will be connected and explained : 

 explanation is, indeed, only relation to something more 

 familiar, not more known i.e. known as to causative or crea- 

 tive agencies. In all phenomena the more closely they are 

 investigated the more are we convinced that, humanly speak- 

 ing, neither matter nor force can be created or annihilated, and 

 that an essential cause is unattainable. 



