cardboard (carta)

Ingredients

cardboard (carta), iron wire, magnet, copper

Preparation Steps

Original Recipe Text

The compass disc is constructed by forming a figure from iron wire with equal sides and unequal angles, creating a deformed rhombus shape. A circular piece of cardboard (known as 'carta') is then adhered to the iron wire figure, with one piece applied from the top and another from the bottom (p. 62). This disk, whose diameter does not exceed the length of the rhombus, includes a copper hollow in its center. The disk is marked with 32 points of direction at intervals of 11 degrees and 25 minutes, representing the rising and setting of 15 fixed stars and the two poles (p. 62).

Evidence

"On this they stick a circular piece of cardboard (carta), one from the top and one from the bottom."

Remarks

This advanced type of compass disc was used in the Indian Ocean and described by the historian Hieronimus Osorius (1506-1580) (p. 62). The cardboard disc provides an optical display of all wind directions. Similar cardboard construction is found in later 19th-century Spanish replicas from the Museu Marítim in Barcelona (Inventory No. C 1.14, p. 73) and the Escuela Nautica Masnou (Inventory No. C 1.15, p. 74).