"My success as a man of science, whatever this may have amounted to,
has been determined, as far as I can judge, by complex and diversified
mental qualities and conditions. Of these, the most important have
been--the love of science--unbounded patience in long reflecting over
any subject--industry in observing and collecting facts--and a fair
share of invention as well as of common sense. With such moderate
abilities as I possess, it is truly surprising that I should have
influenced to a considerable extent the belief of scientific men on some
important points."
Autobiography (1881); "The Life and Letters of Charles Darwin", Vol. 1.
page 107.