PRISMATIC; PRISMATICAL a.
en passed through a prism; primary colors. See Primary colors, under Color. -- Prismatic compass (Surv.), a compass having a prism for viewing a distant object and the compass card at the same time. -- Prismatic spectrum (Opt.), the spectrum produced by the passage of light through a prism.
PROPORTIONAL a.
l to the logarithms of the natural numbers; a logarithmic scale. -- Proportional scales, compasses, dividers, etc. (Draughting), instruments used in making copies of drawings, or drawings of objects, on an enlarged or reduced scale.