The Frequencies of the electric current and the brain patterns were so different that they would not interfere with each other.
"The Electronic Mind Reader"
John Blaine
The tuning fork record, frequency 50 per second, gives the vibration Frequencies.
"Manhood of Humanity."
Alfred Korzybski
Material surfaces, it would appear, reflect them all in equal value, and the color of the resultant picture depends on the color of the foco Frequencies.
"The Airlords of Han"
Philip Francis Nowlan