Christiaan Huygens, a Dutch philosopher and mathematician, was one of the leading scientists in the 17h century. He started by trying to disprove theories that had been established by Ancient Greeks in geometry. He was interested in telescopes and astronomy, anc spent a lot of time designing methods to improve the mechanical and optic performance of telescopes. In his book entitled "Systema Saturnium' published in 1659, he noted the discovery of the rings around the planet Saturn, and made observations about the planets, the Moon, and Orion Nebula. His keen interest in the field of astronomy led him to measure time and other matters that relate to mechanical physics. One of his most important contributions was that he explained the vital principles of classical physics like centripetal force and gravity in a vacuum in another book of his. Huygens also put forward a theory explaining the wave behaviour of light. His reputation as a scientist and a scholar became known worldwide, and remains so to this day.
He was famous as a mathematician and geographer. Eratosthenes produced a reliable, logical method to discover prime numbers. It's known as the sieve of Eratosthenes, and is still important in modern number theory in an updated form. Assuming that the Earth was a sphere, Eratosthenes calculated its size with good accuracy. He also calculated the tilt of Earth's axis fairly accurately. Eratosthenes produced the first map of the world which used meridian lines and parallel lines. These were similar to our modern lines of latitude and longitude. This great scientist can be said to have invented geography. In fact, today we still use the word he invented for this new discipline. Geo' was Greek for Earth' and 'graphy' meant 'field of study." Eratosthenes also wrote books on philosophy, mathematics, astronomy, history, comedy, and poetry. His all-round knowledge made him the ideal choice for the most prestigious job an academic could en