volume I, chapter VI: "On the Affinities and Genealogy of Man", pages 200-201 http://darwin-online.org.uk/content/frameset?pageseq=213&itemID=F937.1&viewtype=image
The sentence "At some future period … the savage races" is often quoted out of context to suggest that Darwin desired this outcome, whereas in fact Darwin simply held that it would occur.
The Descent of Man (1871)
Quotes from book
The Descent of Man, and Selection in Relation to Sex
The Descent of Man, and Selection in Relation to Sex is a book by English naturalist Charles Darwin, first published in 1871, which applies evolutionary theory to human evolution, and details his theory of sexual selection, a form of biological adaptation distinct from, yet interconnected with, natural selection. The book discusses many related issues, including evolutionary psychology, evolutionary ethics, differences between human races, differences between sexes, the dominant role of women in mate choice, and the relevance of the evolutionary theory to society.
second edition (1874), chapter XIX: "Secondary Sexual Characters of Man", pages 561-562 http://darwin-online.org.uk/content/frameset?pageseq=584&itemID=F944&viewtype=image
Darwin quoted Horace in Latin: "For even before Helen (of Troy) a woman was a most hideous cause of war"
The Descent of Man (1871)
volume I, chapter V: "On the Development of the Intellectual and Moral Faculties during Primeval and Civilised Times" (second edition, 1874) pages 133-134 http://darwin-online.org.uk/content/frameset?pageseq=156&itemID=F944&viewtype=image
The last sentence of the first paragraph is often quoted in isolation to make Darwin seem heartless.
The Descent of Man (1871)