Iacobs staffean instrument formerly used for measuring the altitude of the sun; a cross-staff.
Even the navigators of the fifteenth century were aware of the deficiencies of the cross-staff and sought to improve upon it.
A man upon the frame-work controls this wheel, guided by a sight on the frame, and a cross-staff at the end of the field.
Above, it has the small arc of the Davis quadrant with the sliding rod of the cross-staff below.
The vane of a cross-staff, made to slide along it by means of a square socket; it may be set to any of the graduations.
But some kind of a dratted cross-current ketched me and I'm sailin' out to sea, I finds, without compass or cross-staff.
The simplest and crudest form of measurer of which the record has been preserved is known as the cross-staff.
He rubbed his eyes, looked again, adjusting his observation by a cross-staff which had been placed so as to bear upon the point.
The cross-staff had not then come into use, and it was never of much service in low latitudes.