^1 Xew Reading of Relativity. 31 



increment of energy being due to Marcelin and Rice *, the 

 present theory independently arrives at the same conclusion, 

 and, moreover, shows that the critical increment is equal lo a 

 whole number of quanta at the infra-red fundamental. In ;i 

 series of papers, Lewis f has made certain calculations of the 

 critical increments necessary in certain reactions and the 

 frequencies at which this energy is absorbed. He writes 

 the expression given above in the form 



Observed heat of reaction = E — E b 



where E 2 is the sum of the critical increments of the 

 reaotant molecules and E ( , that of the resultant molecules. 

 When the energy is absorbed or evolved at the phase 

 frequency, this expres>ion will only be true if the reactant 

 molecules are completely dissociated into atoms. It is 

 evident from the present hypothesis that the critical incre- 

 ment is a whole number of quanta at the infra-red funda- 

 mental — an amount of energy which may be very much 

 smaller than one quantum at the phase frequency. In such 

 a case impossible results will be obtained if the frequencies 

 are calculated from the critical increments derived from the 

 heats of dissociation of the molecules into atoms. 



III. A Neic Reading of Relativity. 

 By Prof. Frederick Slate %. 



A RECENT paper § has broken ground for a rectified 

 comparison between Einstein's kinematics and New- 

 ton's methods by insisting first upon restoring the broader 

 connexion of force with " Quantity of motion.'' New tribute 

 is paid to the hypnotic power of a current view r to evade 

 challenge, in the delay of this conclusive step towards juster 

 correlation, after the disadvantage within the range of electro- 

 magnetics had been conceded against the narrowed form of 

 Newton's equations. But an undeniable habit has inclined 

 overmuch toward some particulars of rigid dynamics, how- 

 ever aware one is latently that the literal condition of variable 

 mass is often directly natural, and that the devices lie close 

 at hand which fit for parallel treatment the enlarged (or 



* Rep. Brit. Assoc, p. 307 (1915). 



t Trans. Chem. Soc. 1914 to 1919, passim. 



X Communicated by the Author. 



§ Slate, Phil. Mag., April 1930) p. 4:J3. 



