An analysis of the true principles of security against forgery : exemplified by an enquiry into the sufficiency of the American plan for a new bank note : with imitations of four of the most difficult specimens of those notes, made by ordinary means; by which it is proved that there is no adequate security to be achieved in one colour, in the present state of the arts, and that the true basis of security is in the due application of relief engraving, and printing in two or more colours / by William Congreve.