A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Huub Robroek
Date: 2020 Apr 10, 02:35 -0700
the Dutch title on the drawing is:
Design of a Degree Arc ("Graetbogen") and the making thereof.
The other text in the drawing corresponds to the English version visible on "The Making of a Cross Staff", in the link given by Jürgen. (btw: the old Dutch "boeghe" means "arc").
I haven't figured out yet how this cross staff works.