'T Derde deel van 't Licht der zee-vaert, inhoudende de beschryvinghe der zeecusten van de Middelandtsche...

edge), draw a straight line C D. Make a small slider schuyfken small sliding piece like E with a hole F, so that one may place it on the staff A B and slide it back and forth along it, also having a small sight-hole sichtgaetken small sighting aperture across it, like G, in such a way that when that slider is on the staff, that sight-hole then comes to stand exactly level with the center line of the staff C D, neither higher nor lower. Make another slider like H, and on the middle of it also a small sight-hole like K, and an angled hole I, in order to attach it therewith to the outer end of the staff at B, in such a way that it stands not straight,

Technical diagrams illustrate components of a cross-staff:

• Top: Decorative floral ornaments.
• Center: Piece H is a rectangular slider with slot I and hole K. Piece R is an angled fitting. Piece S is a notched component (T, V, X). M-N is a long cross-staff arm. E is a slider with sight-hole G.
• Bottom: A long horizontal rod A-B with center line C-D.

but slanted or tilted on it, according to the indication of the line B D L, and that the sight-hole K comes to stand (like the other sight-hole G on the slider E) neither higher nor lower than the line C D, exactly level with point D. Or, in place of that sight-hole, one may cut the cross-piece itself from the bottom up to the line where the sight-hole stands, as can be seen (on the cross-piece S) the line X V. Make also a cross of one and a half or two feet long, of the form M N, with a hole at N, so that it may be placed at a right angle to the aforementioned