He was now at his worst; madder than he had been earlier in the night.
Mimi, trying to keep as far from him as possible, moved across the stone floor of the turret roof, and found a niche which concealed her.

It was not far from Lady Arabella's place of hiding.
Edgar, left thus alone on the centre of the turret roof, found himself altogether his own master in a way which tended to increase his madness.
He knew that Mimi was close at hand, though he had lost sight of her.

He spoke loudly, and the sound of his own voice, though it was carried from him on the sweeping wind as fast as the words were spoken, seemed to exalt him still more.

Even the raging of the elements round him appeared to add to his exaltation.

To him it seemed that these manifestations were obedient to his own will.