Origin of a Mathematical Symbol for Variation

Abstract

As a contribution to the history of algebraic notation it may be worth while to point out that the symbol for variation was introduced by William Emerson. In his “Doctrine of Fluxions,” third edition, London, 1768(first edition, 1749), he says on p. 4:—“To the common Algebraic Characters already received I add this”, which signifies a general Proportion; thus, A “BC/D, signifies that A is in a constant Ratio to BC/D; that is(if a, b, c, d be other Values of these Quantities) A:BC/D::a:bc/d; and thus every general Proportion is to be understood.”