Tesla's assistant, Mr. Alley, sitting among massive streamers from the Colorado Springs oscillator

Discharge passing laterally to the camera from the central coil to another coil on a stand. Mr. Alley is sitting in the chair. Compare the size of the coils shown with that of the man at the Left. A double exposure was necessary — First with the man and apparatus, then with the apparatus (less the man) fully excited. Sparks measure 22 feet in length.