274 ANNUAL, EEPOKT SMITHSONIAN INSTITUTION, 1910. 



ance is decreased sufficiently to enable the battery E to actuate the 

 relay R. This closes a local circuit, in which the telectrograph re- 

 ceiver is included, and a mark appears on the paper. In this way a 

 visible record is obtained, which greatly facilitates the process. 



Wireless phototelegraphy may eventually prove of more utility 

 than the closed-circuit methods, because it would bring America 

 within reach of this country, and would enable communication to be 

 made where telephone or telegraph lines did not exist. It is not 

 limited to photographs — banking signatures, sketches, maps, plans, 

 and writing could be transmitted. But I would point out most par- 

 ticularly that the work is as yet in the very earliest stages, and that 

 in giving you some account of it to-night I may be bringing before 

 your notice methods and systems on which a few years hence you will 

 look back with a smile — as curious merely from a historical point 

 of view. 



