Tesla's Experiments With Resonance

what follows is part of an article and interview with Tesla by Allan L. Benson,
published in The World To-Day, Vol. XXI, No. 8, February 1912, Page 1763-1767.

The principle embodied in [experiments with resonance] interested Tesla, and he
determined to try it upon a larger scale.  He ordered from a steel company a
steel link, two feet long and two inches thick.  He was careful to specify that
the steel should be of the best quality.  As a matter of fact, the link was
strong enough to bear a weight of hundreds of tons.

Tesla fastened to this link an electric vibrator, no larger than an alarm-
clock, but so constructed that the frequency of the vibrations could be altered
at will.  He set the vibrator to going and then began to vary the vibrations
for the purpose of getting the vibrator in "tune" with the link.  For a long
time, nothing happened -- the vibrations of the link and of the machine did not
chance to coincide. But at last he got them together, the great steel link
began to tremble, increased its trembling until it dilated and contracted like
a beating heart -- and finally broke!

Sledge hammers could not have done it; crowbars could not have done it, but a
fusillade of taps, no one of which would have harmed a baby, did it.

Tesla was pleased.  He had learned something.  He wanted to learn more.  He put
his little vibrator in his coat pocket and went out to hunt a half-erected
steel building.  Down in the Wall Street district, he found one -- ten stories
of steel framework without a brick or a stone laid around it.  He clamped his
vibrator to one of the beams, and fussed with the adjustment until he got it.

"In a few minutes", he said, "I could feel the beam trembling. Gradually, the
trembling increased in intensity and extended throughout the whole great mass
of steel.  Finally, the structure began to creak and weave, and the steel-
workers came to the ground panic-stricken, believing that there had been an
earthquake.  Rumors spread that the building was about to fall, and the police
reserves were called out.  Before anything serious happened, I took off the
vibrator, put it in my pocket and went away.  But if I had kept on ten minutes
more, I could have laid that building flat in the street. And, with the same
vibrator, I could drop Brooklyn Bridge into the East River in less than an

Tesla says that he can split the earth in the same way -- split it as a boy
would split an apple -- and forever end the career of man.

This seems like quite a large order -- but see what he says about it.

"The vibrations of the earth," said he, "have a periodicity of approximately
one hour and forty-nine minutes.  That is to say, if I strike the earth this
instant, a wave of contraction goes through it that will come back in one hour
and forty-nine minutes in the form of expansion.  As a matter of fact, the
earth, like everything else, is in a constant state of vibration.  It is
constantly contracting and expanding.

"Now, suppose that at the precise moment when it begins to contract, I explode
a ton of dynamite.  That accelerates the contraction and, in one hour and
forty-nine minutes, there comes an equally accelerated wave of expansion.  When
the wave of expansion ebbs, suppose I explode another ton of dynamite, thus
further increasing the wave of contraction.  And, suppose this performance be
repeated, time after time.  Is there any doubt as to what would happen?  There
is no doubt in my mind.  The earth would be split in two.  For the first time
in man's history, he has the knowledge with which he may interfere with cosmic

I asked Tesla how long he thought it would take him to split the earth in two.
He said he didn't know.  Months might be required; perhaps a year or two.

"But in a few weeks," he said, "I could set the earth's crust into such a state
of vibration that it would rise and fall hundreds of feet, throwing rivers out
of their beds, wrecking buildings, and practically destroying civilization.

"The principle cannot fail.  It is as powerful when applied to the earth as it
is when applied to a [violin note shattering a] wineglass, a [boy pushing a man
on a] swing, or a steel link.  Any one who doubts should only bear in mind the
illustration of the swing.  A small boy, by each time adding a pound to the
force with which a 200-pound man swings, can soon set the man swinging with the
force of 500 pounds.  It is necessary only to keep adding a little force at the
right time."

 * Origin: RAD BBS, Melrose, Oregon (93:9705/4)