Complex sentence: The title refers to "Walden" (1854) by Henry David Thoreau, where the sound of a locomotive whistle disrupts the natural scene at Walden Pond, a metaphor used by Marx to illustrate the relationship between nature and technology in the United States.
Split into simpler sentences: The title refers to "Walden" (1854) by Henry David Thoreau, where the sound of a locomotive whistle disrupts the natural scene at Walden Pond. Marx uses this metaphor to illustrate the relationship between nature and technology in the United States.