Sentence:  In this way the ancient knowledge of Pythagoras is applied in the most modern form of <WSD>psychophony</WSD>, and in this way, for the first time in the existence of the present world, the special mind-power vibrations which you require are reproduced on the invisible ether, at your command, by the use of the psychophonic records. 
Meaning of the word marked with <WSD> tags:  Vocal communication with the dead or with spirits.