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
On the Origin of Species larvæ of ichneumonidæ feeding within the live bodies of caterpillars, —not as specially endowed or created instincts, but as small consequences of one general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die. Chapter VIII addresses the idea that species had special characteristics that prevented hybrids from being fertile in order to preserve separately created species. Darwin said that, far from being constant, the difficulty in producing hybrids of related species, and the viability and fertility of the hybrids, varied greatly, especially among plants. Sometimes what were widely considered