The great abstract ideas (considered directly and not merely in tacit use) which have dominated the science were due to them - namely, ratio, irrationality, continuity, the point, the straight line, the plane.
In 1761 he proved the irrationality of 7r; a simpler proof was given somewhat later by Legendre.
In one of the notes Legendre gives a proof of the irrationality of 7r.
This property is referred to as the "irrationality of dispersion."
The irrationality of dispersion is well illustrated by C.Christiansen's experiments on the dispersive properties of white powders.
How would you define irrationality? Add your definition here.