312 



TH E TELEPHONOGKAPH. 



papers, and subsequently more fully described in the Electrical World 

 and Engineer, of June 3, L899. The diagram shown in fig. 6 (PI. II) 

 illustrates very clearly the arrangement of the two phonographs, four 

 telephones, two sets of induction coils and batteries and other appa- 

 ratus, circuits, etc., and these experiments constitute. I believe, the 



MAGHETS /A/ PARALLEL. SERIES PARALLEL 



\8AT7ERY 



MAGf/ETS M 3ER/ES PEC0RO/M0 END. REPPODI/C//V0 EA/O. 



\ TELEPROA/E 



I BATTER y VVBATTERT. 



Fig. 5.— Proposed methods for increasing volume of sound and of duplexing. 



first practical form of telephonic relay which has ever been constructed, 

 and which operated with perfect success over 104 miles on the lines of 

 the Long Distance Telephone Company, between New York and Phila- 

 delphia. (It is interesting to note that the sound passed through the 

 air five times, through fifteen separate mediums, and changed its phy- 

 sical characteristics 48 times in transmission.) a 



a See Electrical World and Engineer of June 3, 1899. 



