An Italian surveyor's sector, engraved 'Adam Heroldt fecit Romae'. The sector was invented independantly by Galileo and Thomas Hook at the end of the 16th century. It primarily measures proportions and can contain lines concerning trigonometry, geometrical drawing and calculations on surfaces and volumes. This instrument is on the stand and is pictured with three later examples.



Image number:  10302562

Credit:  Science Museum/Science & Society Picture Library



Date taken:  20 October 2003 13:28

Image rights:  Science Museum