  In spite of the wide range of his book, Cournot did not know some essential
discoveries in natural sciences (William Herschel, Daniel Bernoulli, Humboldt)
and his deliberations about measurement were almost useless. But he introduced
the median and a definition of probability that covered both the discrete and
continuous cases; studied mixtures of densities; qualitatively explained
randomness anticipating one of Poincar\`e's interpretations (small causes
leading to considerable effects) and introducing an embryo of irregularity as a
condition of randomness; introduced a pattern of stratified sampling; attempted
to study dependence between the decisions of jurors; introduced (after J. F.
Fries) philosophical, i.e. qualitative probabilities. Cournot stated that
statistics ought to have its own theory, rules and principles and should
penetrate into the essence of things (which was not yet a received opinion).
Many of his pronouncements were thoughtful and echoed the statistical thought
of the time. In 1849 his book was translated into German.
