 In his 1889, Giuseppe Peano, independently of Peirce and Frege, introduced a notation for universal quantification. If a and b are propositions with the free variables \(x, y, \ldots\), then \(a \mathbin{\revc_{x, y,\ldots}} b\) symbolized: Whatever \(x, y, \ldots\), may be, from the proposition a one deduces b. One hesitates to call this a notation for the universal quantifier, since the quantification is not severable from the sign for material implication: notationally, this is a considerable step backwards from Peirce. Peano moreover does not distinguish first-order from second-order quantification. The point of his essay was to present the principles of arithmetic in logical symbolism, and his formulation of the principle of mathematical induction can be seen, by our lights, to be second-order: but only tacitly. This was a distinction to which (again unlike Peirce) he seems to have attached no importance. He did, however, add a range of new symbols to mathematical logic which were to be influential on the work of Whitehead and Russell in Principia Mathematica; and one of the symbols was the notation \(\exists\) for the existential quantifier. (Oddly, Peano did not introduce a parallel symbol for the universal quantifier. It seems to have been Whitehead who introduced the \((x)\) notation in Principia, and Hilbert who introduced the symbol \(\forall\).)