Non-Euclidean geometry caused a re-examination of the teaching of geometry based on Euclid's Elements. This curriculum issue was hotly debated at the time and was even the subject of a book, "Euclid and his Modern Rivals", written by Charles Lutwidge Dodgson (1832–1898) better known as Lewis Carroll, the author of "Alice in Wonderland". In analytic geometry a plane is described with Cartesian coordinates : "C" = { ("x,y") : "x", "y" ∈ ℝ }. The points are sometimes identified with complex numbers where ε ∈ { –1, 0, 1}. The Euclidean plane corresponds to the case since the modulus of is given
Skeffington Lutwidge September. Lutwidge moved his flag to the new guard ship, the third rate in October, shifting again to in 1799. He became a vice-admiral of the red on 14 February that year, and by 1799 he was commander of the fleets in the Downs, where under his command in 1801 was his former midshipman of the "Carcass" Horatio Nelson, by now in command of . Lutwidge was advanced to admiral of the blue on 1 January 1801, admiral of the white on 9 November 1805, and admiral of the red on 31 July 1810. He retired from active service and