The Rebel Chief by Gustave Aimard

For some minutes after the departure of the guerillero, the melancholy caravan silently continued its journey. The last words uttered by Cuéllar had gone home, however: the count and the _vaquero_ felt involuntarily restless, and without daring to impart their gloomy presentiments to each other, they advanced with excessive prudence, sniffing the air, so to speak, and starting at the least suspicious movement in the bushes. It was a little past five a.m.: it was that moment when nature appears to be sunk in contemplation, and when day and night, struggling together with almost equal force, melt into each other and produce that opaline gleam, whose misty tints impart to objects a vague and undetermined appearance, which renders them somewhat fantastic.

A greyish vapour rose from the ground and produced a transparent fog, which the sunbeams, gradually growing in intensity, rent at spots, lighting up one part of the landscape and leaving the other in shadow: in a word, it was no longer night and not yet day.