Principles, on which it appears that a more perfect system of currency may be formed either in the precious or non-intrinsic metals so as to produce a representative coin or token, the genuineness of which may be instantly determined by a separate gauge, or an intrinsic self-gauging coin, any counterfeit of which must be immediatly detected, however accurate the resemblance or exact the weight - Congreve, William (T. Egerton, 1819)
Goldsmiths'-Kress no. 22521.14. - OCLC, 16958823. - Reproduction of original from Kress Library of Business and Economics, Harvard University