accented contour (_F_) or slightly removed from it, as in Figure 300.

_Inceptive Axes_: For interior surfaces, the radii of the contour circle generally supply the axes of symmetry.

_Points of Concentration_: For interior surfaces, the points of concentration may be placed in or near the radii of the area.

_Ill.u.s.trations_: Figures 302, 303, 304, 305, 306.

_Problems_: Cups, pitchers, steins, nut and rose bowls, low vase forms.

[Sidenote: Low Cylindrical Forms, Plate 49]

(_A_) _Zone of Enrichment_: upper margin of exterior.

[Sidenote: Marginal Enrichment]

_Type of Design_: Borders of units joining each other or connected by bands or spots acting as connecting links. Rule 9c.

_Inceptive Axes_: Vertical elements of the exterior surface.

Elements are imaginary lines dividing the exterior surface into any given number of vertical sections. Elements used as center lines form the axes of symmetry about which the b.u.t.terfly of Figure 308 and similar designs are constructed.

_Points of Concentration_: On each vertical element.

_Ill.u.s.trations_: Figures 308, 309, 310, 311, 312, 316.

[Sidenote: Full Vertical Surface Enrichment]

(_D_) _Zone of Enrichment_: full vertical surface.

_Type of Design_: Extended borders with strongly developed vertical lines or forms. Less than one-half of the surface may be covered.

_Inceptive Axes_: Vertical elements.

_Points of Concentration_: In upper portion of vertical elements, hence in upper portion of area.

_Ill.u.s.trations_: Figures 307, 314, 317, 318.

[Sidenote: High Cylindrical Forms, Plate 50]

(_E_) _Zone of Enrichment_: free balance of full surface. (See _D_, above).

_Ill.u.s.tration_: Figure 315.

_Problems_: Vases, jars, pitchers, tall flower holders, covered jars for tea, crackers, or tobacco.

[Sidenote: Marginal Enrichment]

(_A_) _Zone of Enrichment_: margin of exterior.

_Type of Design_: Borders of geometric units, freely balanced floral units, and other natural motives placed in upper margin of ma.s.s.

_Inceptive Axes_: Vertical elements of cylinder.

_Points of Concentration_: In upper portion of vertical elements.

_Ill.u.s.trations_: Figures 319, 320, 321, 327, 331, 332.

[Sidenote: Full Surface Enrichment]

(_D_) _Zone of Enrichment_: full surface of exterior.

_Type of Design_: Free of formal conventionalized unit repeated on each vertical element. The units may be juxtaposed or may be connected by bands or similar links.

_Inceptive Axes_: Vertical elements of cylinder.

_Point of concentration_: In upper portion of vertical elements.

_Ill.u.s.trations_: Figures 322, 323, 324, 326, 328, 329.

[Sidenote: Types of Commercial Pottery]

The reader should carefully consider the postulate and various divisions of Rule 7 and try to apply them to the material now under consideration.

Acknowledgment is made for material supplied by the Rookwood Potteries for Figures 288, 289, 292, 293, 294, 297, 298, 315; 327 and 332; Newcomb Potteries, Figures 314, 316, 317, 318, 326; Teco Potteries, 329; Keramic Studio Publishing Company, 302, 307, 308, 310, 312.

INSTRUCTION SHEET

Plate 51 ill.u.s.trates the marginal surface enrichment of low cylindrical forms, with part surface enrichment of two higher forms.

SUMMARY OF DESIGN STEPS

(_a_) Draw primary ma.s.s:

For square or rectangular areas draw square rectangle, etc.