What's Bred in the Bone by Grant Allen

All the way home on that long journey from Cape Town, as the two half-brothers lounged on deck together in their canvas chairs, Granville Kelmscott was wholly at a loss to understand what seemed to him Guy Waring's unaccountable and almost incredible levity. The man's conduct didn't in the least resemble that of a person who is returning to give himself up on a charge of wilful murder. On the contrary, Guy showed no signs of remorse or mental agony in any way; he seemed rather elated, instead, at the pleasing thought that he was going home, with his diamonds all turned at the Cape into solid coin, to make his peace once more with his brother Cyril.

To be sure, at times he did casually allude to some expected unpleasantness when he arrived in England; yet he treated it, Granville noticed, as though hanging were at worst but a temporary inconvenience. Granville wondered whether, after all, he could have some complete and crushing answer to that appalling charge; on any other supposition, his spirits and his talk were really little short of what one might expect from a madman.