Sectors - English Style
Although they gradually disappeared from the instrument, scales for making sundials were the most distinctive feature of sectors made in England. These included scales for hours, chords, latitude, and the inclined meridian. Edmund Gunter, who is credited with inventing the English sector, devised logarithmic scales on which calculations could be made with the aid of dividers. These scales later ended up on slide rules, thanks to William Oughtred and others. On sectors, the scales included logarithmic numbers, sines, and tangents. Finally, unlike the other styles of sectors, the English style provided tools for trigonometry (tangent, sine, and secant) and for navigation (rhumbs and longitude).