EVOLUTION
, in Arithmetic and Algebra, denotes the Extraction of the roots out of powers. In which sense it stands opposed to Involution, which is the raising of powers. The note or character that has been used by some Algebraists, to denote Evolution, is ; as the sign of involution is : characters I think sirst used by Dr. Pell.
Evolution, in Geometry, the opening, or unfolding of a curve, and making it describe an Evolvent.
The equable Evolution of the periphery of a circle, or other curve, is such a gradual approach of the circumference to rectitude, as that its parts do all concur, and equally evolve or unbend; so that the same line becomes successively a less arc of a reciprocally greater circle; till at last they change into a straight line.— In the Philos. Trans. N° 260, a new quadratix to the circle is found by this means, being the curve described by the equable Evolution of its periphery.
