10 Dr. Hare's reply to Professor Olmsted. 



however insensibly small may be the spaces in which it oc- 

 curs, however minute the atoms concerned, how otherwise 

 can they be regulated, than by the same laws which are found 

 to hold good in the case of larger spaces, and larger masses. 



Professor Olmsted proceeds : 



" The motions contemplated by the hypothesis, are either ro- 

 tatory, or vibratory ; those supposed, in the refutation, are rec- 

 tilinear, and in one continued direction ; for to no other does the 

 law of percussion adduced apply." 



As this allegation is unsupported by any proof, it can have 

 but little weight. I will however throw my opinion into the 

 opposite scale. I do assert that the law, which I have laid 

 down, is universally applicable where motion is communica- 

 ted, from one moving body, or set of bodies, to another body, 

 or set of bodies, whether the movements be vibratory, rota- 

 tory, or rectilinear. 



If while two planets are revolving, or two pendulums vi- 

 brating, one overtake the other, will not the heavier be least 

 altered from its previous motion ? If two wheels, two globes, 

 or two cylinders, while rapidly rotating, were to come into 

 contact, would not the same law prevail ? 



" The refutation, (says Professor Olmsted,) supposes the par- 

 ticles to come into collision, each upon each ; whereas the hy- 

 pothesis does not warrant the supposition that any two particles 

 ever strike against each other at all. For it is plain that the re- 

 volutions of particles round their own axes, do not bring them 

 into collision with each other, nor do the vibrations of the parti- 

 cles make it necessary to suppose that they ever hit each other ; 

 for if there be space enough between the particles to permit them 

 to vibrate at all, it is clear that they may vibrate without coming 

 into collision." 



" Finally, if they did impinge against one another, it must be 

 remembered that the motion is backwards and forwards, and 

 therefore this is not a case to which the law of percussion, as 

 adduced by Dr. Hare applies." 



" I cannot but think therefore that Dr. Hare has refuted a con- 

 sequence, not of Sir Humphrey Davy's but of his own creating." 



It were obviously as absurd to allege, that particles cannot 

 move without coming into collision, as to assert that the 

 bow of a violin cannot move unless it rub against the strings. 

 Yet as in the one case, friction is necessary to produce mu- 

 sic, so in the other, collision is indispensable to keep the par- 

 ticles asunder. Would the diurnal movements of the planets 

 prevent them from falling into the sun ? Their annual mo- 



