Diagonal Quotes (3 quotes)
He is unworthy of the name of man who is ignorant of the fact that the diagonal of a square is incommensurable with its side.
— Plato
Quoted by Sophie Germain: Mémorie sur les Surfaces Élastiques. In Robert Édouard Moritz, Memorabilia Mathematica (1914), 211
The fundamental idea of these pylons, or great archways, is based on a method of construction peculiar to me, of which the principle consists in giving to the edges of the pyramid a curve of such a nature that this pyramid shall be capable of resisting the force of the wind without necessitating the junction of the edges by diagonals as is usually done.
Writing of his tower after its completion in 1889. As quoted (translated) in 'Eiffel’s Monument His Famous Tower', New York Times (6 Jan 1924), X8.
The game of chess has always fascinated mathematicians, and there is reason to suppose that the possession of great powers of playing that game is in many features very much like the possession of great mathematical ability. There are the different pieces to learn, the pawns, the knights, the bishops, the castles, and the queen and king. The board possesses certain possible combinations of squares, as in rows, diagonals, etc. The pieces are subject to certain rules by which their motions are governed, and there are other rules governing the players. … One has only to increase the number of pieces, to enlarge the field of the board, and to produce new rules which are to govern either the pieces or the player, to have a pretty good idea of what mathematics consists.
In Book review, 'What is Mathematics?', Bulletin American Mathematical Society (May 1912), 18, 386-387.