As Hugh wanders miserably through the night, the author uses simile and metaphor to convey the disconnect between the preacher's message and the reality of a mill-worker's hardscrabble life:
His words passed far over the furnace-tender's grasp, toned to suit another class of culture; they sounded in his ears a very pleasant song in an unknown tongue. He meant to cure this world-cancer with a steady eye that had never glared with hunger, and a hand that neither poverty nor strychnine-whiskey had taught to shake. In this morbid, distorted heart of the Welsh puddler he had failed.
The simile the narrator uses here compares the preacher’s words to "a very pleasant song in an unknown tongue." Although Hugh can hear some of the beauty in the preacher's words, they are functionally meaningless to him. They are not aimed at an audience of people like him. Rather, they are “toned to suit another class of culture,” which Hugh has no access to because of his different life experiences and Welsh immigrant background.
The metaphor of "world-cancer" here refers to the social ills that the preacher wants to help heal; illness, starvation, poverty, injustice. However, because his approach comes from a position of privilege, he can’t speak about those problems in a way that has anything to do with Hugh’s reality. The preacher has never experienced the hardships of poverty, and so his words “have failed” Hugh. Because he has never suffered hunger and the effects of cheap intoxicants like "strychnine-whiskey," the preacher can only speculate about social improvements. In the “morbid, distorted” view of Hugh and people like him, there’s a vast chasm between his good intentions and their results. The preacher's attempts at spiritual guidance fail to address the tangible needs of the workers, even though he tries.
