1$ Prof. J. Joly on Scientific 



the United States to the Eiffel Tower. The system of Dr. 

 de Forrest is, I believe, used in the maritime application of 

 which I am speaking. The installation is at Point Judith 

 at the western approach to Narraganset Bay. Here, in oat- 

 line, is how this marvel is accomplished : — 



A phonograph speaks the words. It cries the name of the 

 lighthouse or lightship into the transmitter. The system is 

 entirely automatic. The movement of a switch starts the 

 phonograph into operation. The voice, translated into aether 

 waves, reaches the antenna on the ship and is there re- 

 translated to the spoken words by a detector and telephone. 

 No training in Morse signals is required. The sailor hears 

 the words just as the householder hears the message in his 

 telephone. It is stated in an account of this system kindly 

 sent to me by the Submarine Signal Company : — " The 

 receiving apparatus is so small and requires so little tuning 

 that for small ships with no operator, the Captain with a few 

 minutes' instruction could pick up and use the signals.'' At 

 Point Judith " the intensity of the sound and radiation of 

 the transmitter are so designed that ships equipped with the 

 ordinary antenna will hear the signals the same approximate 

 distance that the light would be seen in clear weather." 

 There is heard first a voice which cries the name of the 

 Station every five seconds. After every third repetition of 

 the name of the Station a much feebler voice speaks the 

 warning " You are getting closer; keep off." This signal 

 the sailor will only hear when close in to the lighthouse. 

 The instrument accomplishing this marvel has been called 

 the Radiophone. It is intended to set up Radiophones at 

 several stations on the Atlantic and Pacific coasts. 



When in addition to this instrument you fit the vessel 

 with the wireless compass or goniometer — an instrument 

 whereby the directions from which wireless messages are 

 approaching the ship may be approximately determined, — 

 you have an equipment which replaces the use of the light- 

 house in fog or thick weather. It must, however, be 

 remembered that this system, interesting and wonderful as 

 it is, possesses some of the defects of the light signals. Even 

 if the wireless goniometer gave him his angles as accurately 

 as he obtains them by station pointer in clear weather — 

 which is very doubtful — -the distance indications can only 

 depend on the strength of the wireless signal. But here the 

 influence of atmospheric conditions in affecting the amount 

 of absorption of the transmitted energy must introduce 

 capricious variations. Position cannot be fixed without 



