522 Prof. Challis on the Transmutation of Rays of Light, 



(2) The compound character of the motion, and the form of 

 the above function, are independent of the nature of the dis- 

 turbance. 



(3) The number of the separate motions, the directions of 

 their axes, and the values of the arbitrary constants w, \, and c, 

 must be such as to satisfy the circumstances of the disturbance, 

 and will be different for different kinds of disturbance. .: ^\C\^2\\ 



(4) When the sether in motion suffers disturbance by encoun- 

 tering atoms actually or relatively at rest, and the original motion 

 is a simple series of vibrations of the kind above described, or is 

 compounded of several such motions with parallel axes and dif- 

 ferent values of w, \ and c, the result of the disturbance may in 

 either case consist of an indefinite number of separate motions 

 having their axes in various directions, and having values of m, 

 \ and c altogether different from the values of these quantities 

 in the original motion. This general result includes the parti- 

 cular cases in which the axes of the new vibrations are parallel 

 to the common direction of those of the original motions, or de- 



^viate from it by small angular inclinations. 



(5) The limits of the values of X in the disturbed state of the 

 medium depend on the circumstances of the disturbance; and 

 when the disturbance is of the kind mentioned in (4), are not 

 necessarily the same as the limits of the values of \ in the ori- 

 ginal motions. 



(6) The motion in each of the components of the disturbed 

 motion is symmetrical about an axis, whatever be the motions of 

 the disturbmg atoms, or the original motions relatively disturbed 

 by the atoms. 



These properties of a continuous elastic fluid, being assumed 

 to correspond to phsenomena of light, give the following theo- 

 retical results : — 



By (1) and (2) every portion of light consists of rays, and the 

 general character of the rays is independent of the circumstances 

 under which the light is generated. 



^! By (3) the whole quantity of the light, the directions of its 

 propagation, and the intensities, refrangibilities, and phases of 

 the component rays, are dependent on the particular circum- 

 stances of the disturbance. 



When the circumstances of the disturbance are as supposed 

 in (4) (which is the case appropriate to the present inquiry), 

 light may produce new light, which may differ from the original 

 light in intensity, colour, composition, and direction of propaga- 

 tion. This effect I have called a " Transmutation of Rays ;" and 

 I beg it may be understood, that in making use of these terms 

 I mean only to express a result deduced from the mathematical 



