espèces ou races qui l'habitent ("New division of Earth by the different species or races which inhabit it"), published in 1684. In the 18th century the differences among human groups became a focus of scientific investigation. But the scientific classification of phenotypic variation was frequently coupled with racist ideas about innate predispositions of different groups, always attributing the most desirable features to the White, European race and arranging the other races along a continuum of progressively undesirable attributes. The 1735 classification of Carl Linnaeus, inventor of zoological taxonomy, divided the human species Homo sapiens into continental varieties of europaeus, asiaticus, americanus, and afer, each associated with a different humour: sanguine, melancholic, choleric, and phlegmatic, respectively. Homo sapiens europaeus was described as active, acute, and adventurous, whereas Homo sapiens afer was said to be crafty, lazy, and careless. The 1775 treatise "The Natural Varieties of Mankind", by Johann Friedrich Blumenbach proposed five major divisions: the Caucasoid race, the Mongoloid race, the Ethiopian race (later termed Negroid), the American Indian race, and the Malayan race, but he did not propose any hierarchy among the races. Blumenbach also noted the graded transition in appearances from one group to adjacent groups and suggested that "one variety of mankind does so sensibly pass into the other, that you cannot mark out the limits between them". From the 17th through 19th centuries, the merging of folk beliefs about group differences with scientific explanations of those differences produced what Smedley has called an "ideology of race". According to this ideology, races are primordial, natural, enduring and distinct. It was further argued that some groups may be the result of mixture between formerly distinct populations, but that careful study could distinguish the ancestral races that had combined to produce admixed groups. Subsequent influential classifications by Georges Buffon, Petrus Camper and Christoph Meiners all classified "Negros" as inferior to Europeans. In the United States the racial theories of Thomas Jefferson were influential. He saw Africans as inferior to Whites especially in regards to their intellect, and imbued with unnatural sexual appetites, but described Native Americans as equals to whites. Polygenism vs monogenism In the last two decades of the 18th century, the theory of polygenism, the belief that different races had evolved separately in each continent and shared no common ancestor, was advocated in England by historian Edward Long and anatomist Charles White, in Germany by ethnographers Christoph Meiners