"Tell me what is the actual achievement," she said.
"It is this. When you speak into a telephone the vibrations of your voice agitate a sensitive membrane, and by means of electricity the vibrations are conveyed to almost any distance. When Madame Melba sings into the gramophone, her voice agitates the membrane, which in its turn agitates a needle, which in its turn again makes certain marks upon a waxen disc."
"Yes, go on, go on!"
"When I put a certain instrument upon the head of a man or a woman, when I surround the field of emanation by a shield which captures the vibrations, they are conducted to a receiver more delicate and sensitive than anything which has ever been achieved by scientific process before. That receiver collects these vibrations and can transmit them, just in the manner of a telephone or telegraph wire, for almost any distance."
"And at the other end?" Marjorie asked.
"It has been a difficulty of ten long, anxious, unwearying years."
"And now?"
"Now that difficulty has been finally overcome."
"Therefore?"
"What a person thinks in London can be sent in vibrations along a wire to Paris."