a few things:
1. how exactly did you time yourself? as i believe neither the human brain, nor any manually operated stopwatch can accurately measure speed within a 1second interval. you would have to have recorded yourself onto your computer and analysed the file to be accurate to the 0.1sec (for most media players). if so, it would have been sensible (and very easy) for you to upload this small sound bite in support of such a claim.
2. i have no doubt you can assume an octave position with your hands, go spastic and smudge a series of notes in the approximity of the written ones, and do it all within a second. which again is why the sound file would have been extremely helpful in determining the validity/usefulness your claim.
3. i have no doubt horowitz could pull off the first bar in one second, fairly cleanly, given a few attempts. that is 12 consecutive octaves. 70 consecutive octaves is a complete different matter.
1. I was watching the second hand of the studio wall clock, as I always do for = 60.
2. My computer is on the other side of the house from the studio, and my recording equipment is not hip. Nor did I want to spend a lot of time on this, I just wanted to see if it could be done; it can. I hit the notes, I did not approximate them, although as I said initialy the results were not artistic. Try it; let your wrists go limp (the hard part )and keep 4 and 5 in contact with the keys, and go. Sure Hororwitz could do this, certainly Cziffra could, and probably Barere and Lang Lang. And you.
3. Yes, I am no Horowitz; 12 is my limit. I believe he could do this piece at the filmed tempo, but he was an artist, not a mechanic; in the film he is showing off, knowing he will not be heard. He would not have played this fast for a microphone or audience. But he could have.
I heard and saw him play this Etude in 1983, it was the infamous "Horowitz on Drugs Tour", and most of his playing that night was horrendous. The bright spot, Chopin Etudes op.10 #8 in F, op.25 #10(our subject) and op.25 # 7. He missed notes, a lot of his work was a whole or half step off, but these wrong notes were perfectly together and laser clean. The tempo of the b minor Etude was not as fast our film, but was quite fast, with no hint of difficulty in the execution, played from the wrist, with more full body motion than he usually exhibited, resembling a lethargic copy of the film, absent the silent film jerkiness present in all pre-sound film.
Try it; if you're not worried about the sonic result (Horowitz certainly isn't, it's a silent film, he's grinning ear to ear) it will happen. And if one works at something long enough, evantually the walls will crumble. Do you believe the legend of Alexander Dreyschock playing the "Revolutionary" Etude LH in octaves at tempo? Now THAT makes me wonder....