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 those defending immutability of species, and in effect said that the book offered the best explanation "ever published of the manner of formation of species", though he did not agree with it in all respects. He still had the gravest doubts that transmutation would bestialise man. It appears that Darwin had assured Owen that he was looking at everything as resulting from designed laws, which Owen interpreted as showing a shared belief in "Creative Power". Darwin had already made his views clearer to others, telling Lyell that if each step in evolution was providentially planned, the whole procedure would be