Thirlwell looked highly strung but very cool.

A mistake would have disastrous consequences; if he gave way to the strain for a moment, the canoe would sink.

But she knew he would not give way, and it was comforting to see that the half-breed shared her confidence.
He was, no doubt, a _voyageur_ from his boyhood, but it was plain that he did not want to take the steering paddle.
Sometimes, when a savage gust screamed about them and whipped up the spray in clouds, Thirlwell let the sheet run round a pin; sometimes he sank the paddle deep and she saw its handle bend and the blood flush his face.

Drops of sweat ran down his forehead, but his glance was fixed and calm.

The strain on brain and muscle braced without exciting him; he seemed to accept it as something to which he was used.