which are frequently checked the instant they appear.”
Of all classes, perhaps artists are more apt to form a clear cut image of the features of persons whom they meet—particularly if they are portrait painters. There are instances of celebrated portrait painters who were able to execute a good portrait after having once carefully studied the face of the sitter, their memory enabling them to visualize the features at will. Some celebrated teachers of drawing have instructed their scholars to take a sharp hasty glance at a nose, an eye, an ear, or chin, and then to so clearly visualize it that they could draw it perfectly. It is all a matter of interest, attention, and practice. Sir Francis Galton cites the instance of a French teacher who trained his pupils so thoroughly in this direction that after a few months’ practice they had no difficulty in summoning images at will; in holding them steady; and in drawing them correctly. He says of the faculty of visualization thus used: “A faculty that is of importance in all technical and artistic occupations, that gives accuracy to our perceptions, and justice to our generaliza-
