CONCLUDING REMAEKS. 187 



case may be ; so the other affections are only matter moved 

 or molecularly agitated in certain definite directions. We 

 have already considered the hypothesis that the passage of 

 electricity and magnetism causes vibrations in an ether per- 

 meating the bodies through which the current is transmitted, 

 or the application of the same ethereal hypothesis to these 

 imponderables which had previously been applied to light ; 

 many, in speaking of some of the effects, admit that electri- 

 city and magnetism cause or produce by their passage vibra- 

 tions in the particles of matter, but regard the vibrations 

 produced as an occasional, though not always a necessary, 

 effect of the passage of electricity, or of the increment or 

 decrement of magnetism. The view which I have taken is, 

 that such vibrations, molecular polarisations, or motions of 

 some sort from particle to particle, are themselves electricity 

 or magnetism ; or, to express it in the converse, that dynamic 

 electricity and magnetism are themselves motion, and that 

 permanent magnetism, and Franklinic electricity, are static 

 conditions of force bearing a similar relation to motion which 

 tension or gravitation do. 



This theory might well be discussed in greater detail 

 than has been used in this work ; but to do this and to anti- 

 cipate objections would lead into specialities foreign to my 

 present object, in the course of this essay my principal aim 

 having been rather to show the relation of forces as evinced 

 by acknowledged facts, than to enter upon any detailed ex- 

 planation of their specific modes of action. 



Probably man will never know the ultimate structure of 

 matter or the minutiae of molecular actions ; indeed it is 

 scarcely conceivable that the mind can ever attain to this 

 knowledge ; the monad irresolvable by a given microscope 

 may be resolved by an increase in power. Much harm has 

 already been done by attempting hypothetically to dissect 

 matter and to discuss the shapes, sizes, and numbers of at- 

 oms, and their atmospheres of heat, ether, or electricity. 



