29G Prof. r. E. Chase on Momentum and Vis viva. 



7r'M-^?i'' = 



: 30-041 



7r*'M-^ „ 



0-849 



Trm^ „ 



3-135 



TT^M-^ „ 



•098 



TT-^M^ ,, 



•318 



TT^M-h ,, 



•101 



TT M-^ „ 



•032 



Y sec. apli. 



30-470 



b 



9-548 



Hygcia. 



3-121 



" ® 



1-000 



^ sec. per. 



•207 



The probability of undulatory gravitating action is increased 

 by the investigations of Bjerknes, who has shown (^Comptcs 

 Rendns, Ixxxiv. p. 1377) that two spheres having concordant 

 pulsations attract each other inversely as the square of the 

 distance, and that they repel each other according to the 

 same law if their pulsations are opposed. 



The use of the parabola f in representing expanding action 

 is recognized by H. Saintc-Claire Doville, who states, in con- 

 sidering cases where the vapour-densities vary with the tempe- 

 rature (Comptes lie ndus, Ixxxiy. p. 1257), that ''the move- 

 ment of a material point may be accurately enough represented 

 by a parabolic function of the second degree already employed 

 by M. Fizeau." Deville hopes to employ the resulting rela- 

 tions usefnlly in expounding some principles of Thermo- 

 chemistr}^ 



The hypothesis that the radial vis viva of mean rectilineal 

 velocity may be taken as the representation of increments of 

 heat under constant volume, while the radial vis viva of syn- 

 chronous constant velocity will represent simultaneous incre- 

 ments of heat under constant pressure t, assumes that the 

 gaseous condition is perfect. W. M. Hicks (Phil. Mag. June 

 1877) says: — ''If, then, the two atoms of a molecule become 

 separated, there seem only two ways of accounting for it : 

 either their relative motion becomes so large as to overcome 

 the force of attraction; or some external force must act upon 

 them, which can be nothing else than a reaction between them 

 and some other molecule. The latter is the hypothesis I have 

 adopted in the following investigation." Under this hvpo- 

 thesis, by taking the potential energy of combination of a 

 single molecule at its upper limit and with special tempera- 



ture-conditions, he obtains — = 1*423 ; my own ratio, deduced 



G 



from his former hypothesis (see Phil. Mag. Sept. 187 G, y, S) 



c 

 being - = 27^'^-^(7^'^ + 4) = l•4232. If this coincidence is merely 

 c 



accidental, it is very curious. It seems, as I think, to justify 



* 7r'*M= distance of cc Ceutauri. t Proc. S. Phil. Anicr. xvi. p. 507. 

 X Ibid. xiv. p. Gol. 



