The practical challenges associated with building an ark large enough to house all living animal types, and even plants, would have been very considerable. Various editions of the Encyclopædia Britannica reflect the collapse of belief in the historicity of the ark in the face of advancing scientific knowledge. Its 1771 edition offered the following as scientific evidence for the ark's size and capacity: ". . . Buteo and Kircher have proved geometrically, that, taking the common cubit as a foot and a half, the ark was abundantly sufficient for all the animals supposed to be lodged in it . . . the number of species of animals will be found much less than is generally imagined, not amounting to a hundred species of quadrupeds". By the eighth edition (1853–60), the encyclopedia said of the Noah story, "The insuperable difficulties connected with the belief that all other existing species of animals were provided for in the ark are obviated by adopting the suggestion of Bishop Stillingfleet, approved by Matthew Poole . . . and others, that the Deluge did not extend beyond the region of the Earth then inhabited". By the ninth edition, in 1875, no attempt was made to reconcile the Noah story with scientific fact, and it was presented without comment. In the 1960 edition, the article on the ark stated that "Before the days of 'higher criticism' and the rise of the modern scientific views as to the origin of the species, there was much discussion among the learned, and many ingenious and curious theories were advanced, as to the number of animals on the ark".