Surveying instrument. 16th-century artwork of a man pointing a Jacob's staff (Baculus Jacob) or cross-staff towards the top window of a stone tower. This device was an early surveying instrument used to measure angles,heights,and distances. This woodcut is from 'Margarita philosophica' (1503). This work,by the German author Georg Reisch (c.1467-1525),was an encyclopedic compilation of knowledge that became one of the standard textbooks of the time. The topics in its twelve books included grammar,dialectics,rhetoric,arithmetic,music,geometry,astronomy,physics,natural history,physiology,psychology,and ethics |