In the gloom before the break of the day their uniforms glowed a deep purple hue. From across the river the red eyes were still peering. In the eastern sky there was a yellow patch like a rug laid for the feet of the coming sun; and against it, black and patternlike, loomed the gigantic figure of the colonel on a gigantic horse. What mood does the passage convey based on the connotation of the bolded words?