David Livingstone penetration of Africa. At the same time, his missionary travels, "disappearance", and eventual death in Africaand subsequent glorification as a posthumous national hero in 1874led to the founding of several major central African Christian missionary initiatives carried forward in the era of the European "Scramble for Africa". His meeting with Henry Morton Stanley on 10 November 1871 gave rise to the popular quotation "Dr. Livingstone, I presume?" Livingstone was born on 19 March 1813 in the mill town of Blantyre, Scotland in a tenement building for the workers of a cotton factory on the banks of the River Clyde under
19th century in science later in the 19th century by the German mathematician Bernhard Riemann; here no parallel can be found and the angles in a triangle add up to more than 180°. Riemann also developed Riemannian geometry, which unifies and vastly generalizes the three types of geometry. The 19th century saw the beginning of a great deal of abstract algebra. Hermann Grassmann in Germany gave a first version of vector spaces, William Rowan Hamilton in Ireland developed noncommutative algebra. The British mathematician George Boole devised an algebra that soon evolved into what is now called Boolean algebra, in which the only numbers were