484 Professor W. Stirling [May 10, 



bobbin with the Cinematograph, in order that the two pieces of 

 apparatus shall niove synchronously. Any serviceable form of motor 

 may be used for the Phonograph. 



Since then, other arrangements have been adopted. The following 

 diagrams show the arrangements used for taking the pictures, recording 

 the sound, and for reproducing both pictures and sounds, as shown in 

 to-night's demonstration. 



This Figure shows the Projector and the Differential Gearing. 



Two rnotors of identical pattern and of approximately the same 

 power (Fig. 2), for driving the talking machine and the^Cinemato- 

 graph, are actuated from the same source. The armatures of each 

 motor are divided into sections. ?>y means of rings on the elongated 

 axle the corresponding sections of the two armatures are connected 

 together. This arrangement enables the two armatures to act 

 mutually one on the other. Notwithstanding any slight mechanical 

 differences in resistance, perfect synchronism is obtained. 



A rheostat introduced into the circuit enables the operator to 

 vary at will the velocity of the motors, even when they are in action. 



