ROGERS, A. L.—_Experimental Tests of Mathematical Ability and Their Prognostic Value_; Teachers College, Columbia University, 1918. SCRIPTURE, E. W.—“Arithmetical Prodigies”; _American Journal of Psychology_, 1891. SCHMITT, C.—“Extreme Retardation in Arithmetic”; _Elementary School Journal_, 1921. SMITH, J. H.—“Individual Variations in Arithmetic”; _Elementary School Journal_, 1916. TERRY, P. W.—“The Reading Problem in Arithmetic”; _Journal of Educational Psychology_, 1921. THORNDIKE, E. L.—_The Psychology of Arithmetic_; The Macmillan Co., New York, 1921. UHL, W. L.—“The Use of Standardized Material in Arithmetic for Diagnosing Pupils’ Methods of Work”; _Elementary School Journal_, 1917. CHAPTER VII DRAWING I. THE VARIOUS KINDS OF DRAWING Manuel, who has made a careful psychological study of talent in drawing, defines drawing as follows: “The term _drawing_ designates a process of causing, by means of pencil, pen, brush, or other instrument, certain lines or areas, or both, to appear on a given surface.” This definition we may accept, if we add that the lines and areas are intended or can be interpreted to signify something. We should not agree, for instance, that the lines and areas which are caused to appear on the ground by the scratching of a fowl should be included within the definition. Having been thus defined, drawings may be classified into many kinds, in accordance with the technique employed and the meaning conveyed. These kinds are (1) copying, (2) representative drawing, (3) analytical or diagrammatic drawing, (4) impressionistic drawing, (5) symbolic drawing, and (6) caricature. This classification is exclusive of other forms of graphic or representative expression, such as painting, sculpture, and paper-cutting (used in the art of cutting silhouettes). These various kinds of presentations differ as to the psychophysical equipment constituting talent for them. It is therefore impossible, as psychological study has proved, to discuss talent for drawing, without specifying what kind of drawing is under consideration. Talent for painting, sculpture, and cutting silhouettes has been little studied, so that we are not in position to discuss these at the present time, either as processes in themselves or as related to drawing.