182 aiB KELLAND, ON THE DISPERSION OF LIGHT, 



d'a „ /I 33a; 



^ = 2.P, 



(ir ~ \i 



.J ^.5 



^^)3a 



G .r 



which would seem to indicate that the velocity is not altogether inde- 

 pendent of the extent of vibration. 



It wovdd, however, lead us too far into speculations, which, after 

 all, may have little grounds to rest upon, should we pursue what I 

 have here barely alluded to. 



We shall obtain a value of e by dividing p by q, for supposing 

 the wave transmitted parallel to the axis of y, 



2 f 1 ^p___\ „. 



■""-%( ^ ^^^1/ 



^vhich will serve to determine e, if the above numerical quantities can 

 be assigned. 



The numerator can be determined without any considerable diffi- 

 culty, but owing to the very slow convergence of the denominator, 

 I have not been able to assign its value to any degree of accuracy, 

 I shall consequently content myself with proving (what is essential to 

 my remarks on the transversality of the vibrations) that each of the 

 quantities is positive. 



