156 Master Minds of Modern Science 



Marconi and his party had four staterooms on the upper 

 deck, and in one of these the instrument was installed. 

 For sending purposes this instrument was not capable of 

 more than one hundred and fifty miles, and it was an- 

 nounced that no commercial messages would be received 

 or sent. Four aerial wires running to the head of the 

 mast were used for reception, and one wire was passed 

 over the side of the vessel, establishing an earth. At 

 Poldhu dynamos created an energy of twenty thousand 

 volts, and this high tension was transformed up to two 

 hundred and fifty thousand by means of condensers. 

 When the operator pressed the key a spark a foot long 

 and as thick as a man's wrist sprang across the gap. It 

 was the most powerful electric flash which man had ever 

 produced. 



The Philadelphia left Cherbourg just before midnight 

 on Saturday, and messages were received and sent until the 

 one hundred and fifty mile limit was passed. Very much 

 passed, indeed, for the ship was two hundred and fifty 

 miles from Poldhu when the last message was received by 

 the land station. On Monday morning Chief Officer 

 Marsden was in the cabin when a message was ticked out : 

 "All in order. Do you understand? " The ship was 

 then fully five hundred miles from Poldhu, and Marsden, 

 full of excitement, ran out to tell his fellow officers of the 

 feat. They laughed. 



Do you expect us to believe that ? " they jeered. 

 All right," smiled Marsden. " Just wait till to- 

 morrow." Next morning the officers crowded in the 

 operating cabin, where Marconi sat, watch in hand. He 

 opened a brake on a coil of tape and the white strip began 

 to unroll. 



" Here it comes," said Marconi calmly, and tap-tap-tap 

 began the inker, recording messages sent out from a source 

 nearly one thousand miles away. 



The days following were full of excitement for every 



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