The camp began to stir as the first white smoke rose from its field kitchens. Through his lenses, the hunter in the grass watched the first bearded infantrymen of the Volunteers forming a queue with their mess-tins for pressed beef, hardtack, and tea. As the sunís warmth began to penetrate the cold air of the plain, a long mounted column was forming up by the main body of the tents. Sound carries far at such an hour and in such stillness. The shifting and snorting of horses, the clink of bridles, drifted through the clear air towards the eastern slopes.
What does stillness imply in this context - silence or the absence of movement?
Both. The lack of activity means there is a lack of noise. Local noise, that is. He could hear the noise of the approaching army.