Retta linea gnomonica
Retta linea gnomonica is a 1675 treatise on sundial construction by Giuseppe Maria Figatelli, printed at Modena by Viviano Soliani, printer to the ducal court, for mathematicians and instrument makers. Its diagrams are geometric line drawings of circles, meridians, shadow lines and hour-numbered dials, with letter labels and plain black ink on cream paper, offering a designer clean schematic motifs of arcs, radiating lines and numbered rings.
