Ape and human skulls. Historical artwork of skulls and faces of a series of apes and humans. This depicts the course of evolution of the human skull from that of the lower apes. The artist and anatomist Pieter Camper (1722-1789) devised a method of measuring the facial angle of the skull. He asserted that the more vertical the facial angle, the closer it was to the 'perfect' head. This artwork was published in London in 1794 in The works of the late Professor Camper on the Connexion between the Science of Anatomy and the Arts of Drawing, Painting, Statuary.