A clever instrument for observing slope and computing distance simultaneously.
In: Geometriae practicae novae et auctae tractatus I[-IV] ... By Daniel
Schwenter, 1585-1636. Published posthumously in 1641. Book 3, page 38.
Call Number TA544 .S38 1641
Image ID: libr0034, Treasures of the NOAA Library Collection Photographer: Archival Photograph by Mr. Sean Linehan, NOS, NGS
