The Countess was silent, then her voice grew firmer.

At first the phenomenon was thin, then it grew firmer, denser.

As my vision began to clear, my voice grew firmer.

He spoke haltingly at first, his voice growing firmer as he went on.

The moonlight seemed to grow firmer as her vision cleared.

With each footfall the ground grew firmer beneath his feet.

Slowly they saw the outlines grow firmer until soon a whole city lay spread across the desert.

The sagging bag itself began to fill out and grow firmer inside its web of netting.

His voice grew firmer as he cited a higher authority.

"That's the way it is, Anton," he said after a while, and his voice grew firmer.