In pictures there have been whole generations of imitators and copyists. The continent in the eighteenth century was flooded with sham Correggios, Claudes, Poussins, and Cuyps, and many English painters, afterwards well known, did not disdain to make copies for the dealers of old masters' pictures. David Allan, called the "Scottish Hogarth," was an adept in copying chalk drawings from the old masters; and many artists eked out a pitiable existence as copyists while waiting for the public to acclaim their original work. John Jackson copied the head of Reynolds for Chantrey which could have passed for the original by Sir Joshua. A Rubens he painted in the presence of the students of the Royal Academy was acclaimed as faithful to the original. He was unequalled in such facsimile imitations. Henry Liverseege, in the early days of the nineteenth century, copied Vandyck, Rubens, and Teniers with such skill that few could say which was the original and which the copy. Two pictures, one by Sir Edwin Landseer, and the other a copy, were to be sold on successive days at auction. The painter, strolling in to the auction room on the day before the copy was sold, mistook it for his own work. At the galleries of the Fine Art Society, in Bond Street in 1875, an exhibition was held of a series of facsimiles of Turner drawings in the National Gallery lent by Ruskin and executed for him by Mr. Ward. Of these replicas, Ruskin said in a note: "I have given my best attention during upwards of ten years to train a copyist to perfect fidelity in rendering the works of Turner, and have now succeeded in enabling him to produce facsimiles so close as to look like replicas--facsimiles which I must sign with my own name to prevent their being sold for real Turner vignettes." =Economic Substitution.=--But imitation has many phases. Modern photography in copying the great works of old masters has made it possible to study their works with exactitude in the dimensions of black and white, and if the work is an etching or an engraving the reproduction claims a closer relationship with the original. The art of engraving from painters' work is imitative to the extent that it depicts the same subject and takes its initial inspiration from the painted canvas. But it claims a much higher regard--the great school of interpretative engravers translated painting into terms of black and white.