74. Sector and six-inch rulers
author and place unknown
16 x 3.5 cm, 15 x 3.5 cm, 16.6 x 2.6 cm

These are three instruments the maker of which is unknown: a six-inch sector [Inv MdS-85] with the six basic scales engraved [file 72] and two rulers for dividing the plane line of the compass itself, subdivided in equal parts by the transversal method, these too of six inches [Inv. MdS-86] [Inv. MdS-87].

F. Farinelli (1979), p. 193.