Protractor on the dial from 180°, as the dial is graduated from opposite zero marks to 90° each way. Since the spaces, both on the main scale and the Vernier scale, are numbered both to the right and to the left from zero, any angle can be measured. The readings can be taken either to the right or to the left, according to the direction in which the zero on the main scale is moved. Reading the Vernier scale: The bevel protractor Vernier scale may have graduations of 5′ (minutes) or 1/12°. Each space on the Vernier scale is 5′ less
Savilian Professor of Geometry world, saying that the professor of geometry should teach Euclid's "Elements", Apollonius's "Conics", and the works of Archimedes; tuition in trigonometry was to be shared by the two professors. As many students would have had little mathematical knowledge, the professors were also permitted to provide instruction in basic mathematics in English (as opposed to Latin, the language used in education at Oxford at the time). Savile's first choice for the professorship of geometry was Edmund Gunter, Professor of Astronomy at Gresham College, London. It was reported that Gunter demonstrated the use of his sector and quadrant, but Savile regarded this