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machine from outside, and it would do 

 part of the work of heating the circuit. 

 Thus the two problems, of transmission 

 of power and working in series, were 

 really parts of the same general problem. 

 The points Q and R were the positions of 

 E where these problems passed one into 

 the other, namely, where the output was 

 zero. Through D draw a diameter to the 

 E circle parallel to A B, or 3 D 4, and a 

 second diameter through K, the bisection 

 of A B, or 2 DK 1. It would be seen 

 that these two diameters were equally 

 inclined to A D. The points upon the 

 E-circle so obtained had the following 

 peculiarities : — If E coincided with 1, the 

 maximum power would be given out by 

 the second machine ; if E coincided with 

 2, the maximum power existed which 

 could be employed upon the second 

 machine ; if E coincided with 3, the mini- 

 mum power existed of the first machine ; 

 if E coincided with 4, the maximum 

 power existed of the first machine. Fur- 

 ther, if E lay upon the semi-circle 1 Q 2, 

 there was stability for the second 



