Ok, to simplify, from the top of C, slide down the key, moving the whole hand towards yourself, changing to 2 on D, then arriving at the bottom of the key on E - finger 3. Back to the top of the key on F, same 1234. This is done slowly, exagerated, as it speeds up less and less motion.
It was shown to me as a technique advocated by Michaelangeli, to promote a 'sliding' over the keys (how to put it...), where the thumb is the 'axis' of the slide, as opposed to a more vertical motion of the fingers, with a horizontal motion of arm. The outcome of which is to develop faster scales that retain a clear legato or staccato - which means an even tone.