At first they suggested moles crawling through plow furrows; then, as they progressed onward, they shrank to the smallness of gray grub-worms, advancing one behind another.

My eye strayed beyond them a fair distance and fell on a row of tiny scarlet dots, like cochineal bugs, showing minutely but clearly against the green-yellow face of a ridgy field well inside the forward batteries of the French and English.

At that same instant the lieutenant must have seen the crawling red line too.

He pointed to it.
"Frenchmen," he said; "French infantrymen's trousers.

One cannot make out their coats, but their red trousers show as they wriggle forward on their faces." Better than ever before I realized the idiocy of sending men to fight in garments that make vivid targets of them.
My companion may have come up for pleasure, but if business obtruded itself on him he did not neglect it.