Harry vs ferrovax

"Well," Ferro said. "Let's see if we can't make an impression."
I clutched my cane and gathered up my will, but I was way, way too slow. Ferro just waved a hand vaguely in my direction, and something crushed me down to the earth, as though I suddenly had gained about five thousand pounds. I felt my lungs strain to haul in a breath, and my vision clouded over with stars and went black. I tried to gather up my magic, to thrust the force away from me, but I couldn't focus, couldn't speak.
Michael looked down at me dispassionately, then said, to Ferro, "Siriothrax should have learned that trick. It might have kept me from killing him."
Ferro's cold regard swept back to Michael, bringing with it a tiny lessening in the pressure - not much, but enough that I could gasp out, "Riflettum," and focus my will against it. Ferro's spell cracked and began to flake apart. I saw him look at me, sensed that he could have renewed the effort without difficulty. He didn't. I climbed back to my feet, gasping quietly.


Grave Peril Chapter 26, Page 269-270