On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection Letter" from Darwin to Asa Gray. This was the first announcement of the Darwin – Wallace theory of evolution by natural selection; the papers appeared in print on 20 August 1858. The presentation of the papers spurred Darwin to write a condensed "abstract" of his "big book" on "Natural Selection". This was published in November 1859 as "On the Origin of Species". On the voyage of the "Beagle" the young Charles Darwin took a break between graduating and starting his career as a clergyman to study the natural history of South America, an interest he had developed at the University
Essay on the Origin of Languages Essay on the Origin of Languages Essay on the Origin of Languages () is an essay by Jean-Jacques Rousseau published posthumously in 1781. Rousseau had meant to publish the essay in a short volume which was also to include essays "On Theatrical Imitation" and "The Levite of Ephraim." In the preface to this would-be volume, Rousseau wrote that the "Essay" was originally meant to be included in the "Discourse on Inequality", but was omitted because it "was too long and out of place". The essay was mentioned in Rousseau's 1762 book, "Emile". In this text, Rousseau lays out a narrative