"Nikola Tesla is 79 years old, and he is one of the true geniuses of this time. Nevertheless, twenty-odd newspapermen came away from his Hotel New Yorker birthday party yesterday, which lasted six hours, feeling hesitantly that something was wrong either with the old man’s mind or else with their own, for Dr. Tesla, serene in an old-fashioned Prince Albert and courtly in a way that seems to have gone out of this world, announced that:
1. He had discovered the so-called cosmic ray in 1896, at least five years before any other scientist took it up and twenty years before it became popular among scientists, and he is now convinced that many of the cosmic particles travel fifty times faster than light, some of them 500 times faster.
2. He has found a way to produce a direct electric current by induction and without the use of a commutator, which is something the experts in electricity have considered impossible for the past hundred years.
3. He has invented an “absolutely impossible” machine which will impart vibrations to the earth which, with proper receiving apparatus can be picked up anywhere on the earth’s surface, and that this mysterious machine will allow scientists to explore the deep interior of the earth, will enable practical geologists to discover gold, coal and petroleum, and at the same time will give ships the means of navigating without compass or sextant.
Dr. Tesla has 600 to 700 patents to his name. He invented the rotary field motor, and is admittedly the seer and father of all modern electrical development. As has been his custom for five years now, he arranged his own birthday party, drank only hot milk as his part of the celebration, and made his announcements with the superb certainty of a man who knew what he was talking about, even if none of his guests did.
He said, among other things, that he expects to have $100,000,000 within two years, and he revealed that an earthquake which drew police and ambulances to the region of his laboratory at 48 E. Houston St. in 1887 or 1888 was the result of a little machine he was experimenting with at that time which “you could put in your overcoat pocket.”
The bewildered newspapermen pounced upon this as at least one thing they could understand and “the father of modern electricity” told what had happened as follows:
“I was experimenting with vibrations. I had one of my machines going and I wanted to see if I could get it in tune with the vibration of the building. I put it up notch after notch. There was a peculiar cracking sound.
“I asked my assistants where did the sound come from. They did not know. I put the machine up a few more notches. There was a louder cracking sound. I knew I was approaching the vibration of the steel building. I pushed the machine a little higher.
“Suddenly all the heavy machinery in the place was flying around. I grabbed a hammer and broke the machine. The building would have been down about our ears in another few minutes. Outside in the street there was pandemonium. The police and ambulances arrived. I told my assistants to say nothing. We told the police it must have been an earthquake. That’s all they ever knew about it.”
Some shrewd reporter asked Dr. Tesla at this point what he would need to destroy the Empire State Building and the doctor replied:
“Five pounds of air pressure. If I attached the proper oscillating machine on a girder that is all the force I would need, five pounds. Vibration will do anything. It would only be necessary to step up the vibrations of the machine to fit the natural vibration of the building and the building would come crashing down. That’s why soldiers always break step crossing a bridge.”
His early experiments in vibration, he explained, led to his invention of his “Earth vibrating machine. Tall and thin and ascetic face, his eyes sunken but …. humorous under protruding brows, he was cagey about describing what his new machine is, although he believes it will be "the chief thing of my many inventions posterity will thank me for.“
— Earl Sparling
“Nikola Tesla, At 79, Uses Earth To Transmit Signals.” New York World Telegram, July 11, 1935.