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
Campbell Dodgson the War Office; his 1918 CBE was a recognition of this work (DNB, 1941-50 : 216). He was the editor, in the 1920s, of "The Print Collector’s Quarterly". He was also a contributor to the "Burlington Magazine" and to the Dictionary of National Biography. Dodgson married Frances Catherine Spooner, daughter of William Archibald Spooner (Warden of New College and the eponymous author of 'Spoonerisms'), in 1913 (DNB, 1941-50 : 216). Dodgson gave generously to the British Museum during his Keepership, but at the same time amassed a very large collection of over 5,000 prints which he bequeathed to the Museum.