60 PROCEEDINGS OF THE AMERICAN ACADEMY. 



The T-leak admittance is now 

 , ... cosh S coshS^. G fc , /iA _. 



* = » sinh ^ ■ c^ • c^shy, • g; b mbos < 100 > 



„ ~cr cosh 1.888,071 cosh 0.5 2,193.82 



= 0.001 • sinh 2.492,025 • ^^^ ■ cosho . 388)071 ' ^T^ 2 



= 19.815 X 10 -8 mho. 



Formula (87) then applies without change. 



Repeating the process from the opposite end of the line, as at A 4 F 4 , 

 we have 



cosh l D cosh S B G fB 

 cosh 8 E cosh 8 C G fC 



g^yzsinhSr.—^.- 

 = 19.815 X 10~ 8 mho. 



Formula (89) then applies without change. 



The effect of the load on the T-leak admittance formulas (86) and. 

 (88) is to alter them in the ratio of the impedances or admittances 

 across the load, applying the said ratio in such a manner as to increase 

 the result in the direct-current case. 



Equivalent T. Second Method. 



Formulas (90) and (91) of the alternative method are not altered by 

 an intermediate impedance load, after the line-angles have been prop- 

 erly assigned. 



Equivalence of Alternating-Current Transformers to Impedance Loads. 



It may be observed that since the insertion of a transformer into a 

 circuit, as, for example, the insertion of a " repeating-coil " into a tele- 

 phone circuit, is theoretically equivalent to the insertion of impedance 

 into the circuit without rupture of continuity, all cases of line trans- 

 formers are capable of being dealt with by substituting for such trans- 

 formers their equivalent intermediate impedance loads. 5 



Terminal Impedance Loads. 



A terminal impedance load is likely to present itself in a composite 

 line, owing to the presence of terminal apparatus. The architrave im- 

 pedance of a composite line l~l, computed without any terminal load, 

 can only represent the receiving- end impedance of the line when the 



5 "On the Predetermination of the Regulation of Alternating-Current 

 Transformers," A. E. Kennelly, Electrical World and Engineer, Sept. 2, 1899, 

 Vol. 34, p. 343. 



