Reactions to On the Origin of Species man to be envious of a naturalist like myself, immeasurably his inferior!" Darwin's had estimated that erosion of the Weald would take 300 million years, but in the second edition of "On the Origin of Species" published on 7 January 1860 he accepted that it would be safer to allow 150 million to 200 million years. Geologists knew the earth was ancient, but had felt unable to put realistic figures on the duration of past geological changes. Darwin's book provided a new impetus to quantifying geological time. His most prominent critic, John Phillips, had investigated how temperatures increased with depth
Reactions to On the Origin of Species breeding that would eventually form part of "The Variation of Animals and Plants under Domestication". He wrote to Asa Gray and used the example of fantail pigeons to argue against Gray's belief "that variation has been led along certain beneficial lines", with the implication of Creationism rather than Natural Selection. Over the winter he organised a third edition of the "Origin", adding an introductory historical sketch. Asa Gray had published three supportive articles in the "Atlantic Monthly". Darwin persuaded Gray to publish them as a pamphlet, and was delighted when Gray came up with the title of "Natural Selection Not