156 BULLETIN OF THE 



require very nearly two seconds for its transmission *and delivery at 

 the opposite end. Or if we reduce our steel punch to the more 

 manageable length of (let us say) one foot, then the blow received 

 by it from a hammer, and the blow given out by it at the other 

 end, will be separated by the interval of the 18,000th part of a 

 second. Assuming the actual approach of the hammer face to the 

 end of the steel punch at the instant of impact to be the millionth 

 of an inch, we may even compute the interval of time elapsing 

 between the delivery of the blow by the hammer and its reception 

 by the steel punch, at the 1 -=- 216000,000000 of a second; an 

 interval of time real enough and long enough to permit the atoms 

 of the iron molecules to execute from 1800 to 3200 of their normal 

 oscillations or orbital revolutions. By thus considering what is 

 really signified by physical contact and impact, we find it to be 

 something quite different from what the kinematist would suggest 

 by his appeals to " the sense of touch." 



The unlucky boy when struck in the face with a ball, or wounded 

 in his finger with his jack-knife, may well refuse to be comforted by 

 the assurance that neither the ball which bruised his face, nor the 

 blade which penetrated and severed the capillary vessels of his 

 finger, ever approached within the millionth of an inch of his flesh, 

 or probably within double that distance from it. But the philoso- 

 pher who aspires to construct a theory of universal force from the 

 inductions of experience, should at least sufficiently develop his in- 

 tellectual vision to avoid accepting coarse and external resemblances 

 as evidences of co-ordinated derivation, or adopting the unanalyzed 

 impressions of unobservant consciousness as the revelations of axio- 

 matic truth. 



Action at a Distance. — But here our investigation is undermining 

 the very corner-stone of the kinematic system, — the repudiation of 

 all static energy, the alleged fundamental absurdity of any me- 

 chanical action at a distance. That " a thing can no more act 

 where it is not than when it is not," is a plain dictum of common- 

 sense.* Even the provisional admission of such a supposition is 



to show the black spot of Newton's rings, which indicates a distance of 

 about a ten-thousandth of a millimeter." (Encyclopcedia Britannica. 9th 

 ed. 1875: art. "Attraction:" vol. in, p. 63.) 



*Prof. James Croll believes that " No principle will ever be generally 

 received that stands in opposition to the old adage ' A thing cannot act 



