KINETIC THEORIES OF GRAVITATION. 229 



of the aether indicate a community of nature with the absolute atoms of 

 the molecule, whose tremblings they transmit, we are confronted with 

 the paradox, that while in the molecule these atoms are so firmly bound 

 together that no known forces have ever been able to divorce them, in 

 their isolated or discrete state constituting " the mother-liquor of the 

 world,-' their repulsions are so intense that no known forces have ever 

 been able to unite them. 



It is impossible not to be struck with the originality of speculation 

 and the ingenuity of experimentation by which, as Dr. Guyot believes, 

 he has solved the great problem of energy or dynamic. But it is appa- 

 rent at a glance that his system is at variance with every feature of the 

 actual phenomenon of gravitation, and fails to represent any of the six 

 conditions-precedent, perhaps excepting the first. If the resultant mo- 

 tion of translation from an acoustic vibration of air (or from a thermal 

 vibration of sether) may be supposed to occur in a right line, it is not 

 established that it can so continue for any considerable distance ; and 

 the last five conditions are each and all directly incompatible with the 

 assumption. 



Perhaps the most palpable fault of the scheme however, is the vio- 

 lence done by it to the established law of the conservation of energy, 

 while being proclaimed apparently in the interest of that law. A 

 vibrating molecule is supposed to impress its motion upon an investing 

 medium, without parting with any of its original vis viva ; or in other 

 words, it is miraculously endowed with an inexhaustible fund of dynamic 

 action, and its motion though constantly expended in "work" per- 

 formed, yet requires no regeneration. 



Or on the other hand, if gravitation depend upon the vibrations 

 transmitted from the active molecule as a center to the surrounding 

 aether, this "attractive" action must decline with the expenditure of 

 the vibratory energy, contrary to the observed fact as summed up in 

 the sixth proposition. 



Faraday. 1844. 



Although the views announced by Professor Michael Faraday on the 

 subject of gravitation were undoubtedly very vague, he must be classed 

 with the kinetic theorists ; and the very influence necessarily attaching 

 to his well-earned reputation as an investigator and experimental physi- 

 cist, renders a full discussion and a free criticism of his published reflec- 

 tions all the more imperative in the interests of scientific truth. 



In "A Speculation on the Nature of Matter,' 7 dated January 25, 1844, 

 Faraday remarks : "The safest coarse appears to be to assume as little 

 as possible ; and in that respect, the atoms of Boscovich appear to me 



to have a great advantage over the usual notion A mind 



just entering on the subject may consider it difficult to think of the 



powers of matter independent of a separate something to be called the 



v matter, but it is certainly far more difficult, and indeed impossible, to 



think of or imagine that matter, independent of the powers. Now the 



