576 Prof. A. L. Narayan on a Mechanical Illustration 



the Jengtb of A so as to rotate about a parallel axis 0'. 

 Similarly, C is attached to A. Thus the degree of coupling 

 between the various circuits can be varied at will. 



It is worth noting that, at first, the three pendulums were 

 connected as shown in photograph fig. I. ; but subsequently 

 as it was found that owing to want of symmetry in the load 

 the pendulum A began to tilt slightly to one side as the 

 coupling was increased, the arrangement shown in photograph 

 fig. II. was adopted throughout. And it may be noted that 

 there is essentially no difference between these two arrange- 

 ments, as can be seen from the fact that in either case 

 we get a cubic in w 2 , thereby showing that the resultant 

 motion in each case is composed of three superposed simple 

 harmonic motions. 



The paper includes ten photographic traces of the motion 

 of the pendulums under various conditions, the method 

 adopted for photographing these vibrations being exactly 

 the same as that adopted by the author in his previous 

 experiments. For a detailed description of this method, 

 the reader is referred to his previous paper on coupled 

 oscillations *. 



Equations of motion and coupling of the mechanical system. 



The annexed figure represents a projection of the three 

 pendulums on a vertical plane, perpendicular to the axes 

 of rotation. 



' p. 567. 



iupriif 



