Influence of variable alumina and silica on the relative viscosity of a porcelain glaze
A 1914 ceramic engineering thesis by Sidney Isaac Sewell, submitted at the University of Illinois, measuring how varying alumina and silica change the viscosity of a porcelain glaze. The plates are hand-lettered line graphs drawn on pale green graph paper, each a fan of smooth descending curves labelled with silica ratios against a temperature axis, useful for grid textures, technical chart motifs, and hand-drawn annotation styles.
