154 BULLETIN OF THE 



It is the inversion of the sequence taught us by all'sufficiently ob- 

 servant experience, that motion of any kind or form is ever the 

 product of force, and can never be its parent. 



Inadequacy of a Vibratory Hypothesis. — But after all this lavish 

 exercise of creative power and ingenuity, — this prodigal expendi- 

 ture of kinetic energy, — how surprising to find the notable inven- 

 tion wholly incompetent to produce the observed phenomena. Co- 

 hesive force (for example) apparently incapable of exerting any 

 attractive power whatever beyond the range of a single layer of 

 molecules, that is beyond the distance of perhaps the five hundred 

 millionth of an inch from its center of action, yet exercises for an 

 exceedingly small space within that distance a holding strength 

 many thousands of times greater than the all-pervading power of 

 gravitation. By what form of undulation, oscillation, or impulsion, 

 shall we represent the tenacity of a steel wire sustaining a pull of 

 300,000 pounds to the square inch beyond the limits of perhaps the 

 thousand-millionth of an inch between its molecules, yet exerting 

 within that limit an insuperable repulsion, and again at double the 

 distance another range of repulsion, so far resisting all human 

 efforts, that the nicest and closest approximation of the severed ends 

 of the wire shall fail to develop the attraction of an ounce or single 

 grain?* By what form of partial differential equation, shall this 

 sudden aud absolute discontinuity of function be expounded ? Nay 

 rather, by what hallucination of metaphysical assumption have in- 

 telligent men been induced to waste useful time and ink and paper, 

 on the chase of the ignis-fatuus of cohesive undulation or percus- 

 sion ? 



The Authority of " Sensible " Impressions. — But it is insisted that 

 "the principle of deriving fundamental conceptions from the indi- 

 cations of the senses does not admit of regarding any force varying 

 with distance as an essential quality of matter, because according 



* Prof. Challis thinks "the ultimate atoms of glass are kept asunder 

 by the repulsion of setherial undulations which have their origin at indi- 

 vidual atoms," and " it may be presumed that this atomic repulsion is attrib- 

 utable to undulations incomparably smaller than those which-cause the 

 sensation of light." [Principles of Mathematics and Physics. 18G9 : p. 456.) 

 But the luminifcrous vibrations are themselves atomic. What lower order 

 of atom is then to be appealed to in support of this fanciful and inept 

 hypothesis ? 



