King Coal by Upton Sinclair

Knowing these people well, Hal could measure the effect of the thunderbolt he had hurled among them. They were people to whom good taste was the first of all the virtues; he knew how he was offending them. If he was to win them to the least extent, he must explain his presence here -- a trespasser upon the property of the Harrigans.

"Percy," he continued, "you remember how you used to jump on me last year at college, because I listened to ‘muckrakers. ' You saw fit to take personal offence at it. You knew that their tales couldn't be true. But I wanted to see for myself, so I went to work in a coal-mine. I saw the explosion; I saw this man, Jeff Cotton, driving women and children away from the pit-mouth with blows and curses. I set out to help the men in the mine, and the marshal rushed me out of camp. He told me that if I didn't go about my business, something would happen to me on a dark night. And you see -- this is a dark night!"