I just read this in one of Tesla's transcripts

A radio wave has electric and magnetic components so we call it an electromagnetic wave.

What Testa is describing in the quote is probably an invention of his famous "Tesla Coil" he built in Denver Colorado, that transmitted alot of power at the time.

 

It ws teslas dream to produce power and transmit it via the ionsphere....
He said that wherever you were on the planet, you could get your power by tuning into it...
Most of his patent applications are still under US national security audit and haven't been released.
Seven years after his death, a court decided that the seven most important patents granted to marconi under the wireless section belonged to tesla.

 

check out the varian brothers. klystron tube shop at stanford. ilc in germany. hutchinson effect.(( and the philli experiment ( someones imagination of what tesla was talking about) ))
hope i do not get suspended for this.

 

As I understand Tesla's Tesla coil transmitter, a great deal of the power passed via ground transmission rather than electromagnetic waves. That he should call it electromagnetic activity is a matter of evolving symmantics. Electromagnetic theory was an evolving science at the time, still soft in spots.