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When we talk about Philosophy, the first name that comes into our mind is that of Aristotle (384 BC- 322 BC) who followed a comprehensive system of ideas about human nature and the nature of the reality we live in. Early Life and Contributions:One of the prominent names of history, this famous personality was a Greek philosopher, was born in Stagira in North Greece, the son of Nichomachus, the court physician to the Macedonian royal family. He was trained first in medicine, and then in 367BC was sent to Athens to study philosophy with Plato. He stayed at Platos Academy until about 347. He has also been under the supervision of Alexander the Great.Aristotle is one of the most important founding figures in his time as his writings constitute a first at creating a broad system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics. Besides this his piece of work also includes other subjects, including physics, poetry, theater, music, rhetoric, government and ethics. The scientific field has witnessed the emergence of many great physicists and chemists; but it is incomplete without the mention of the great British chemist, meteorologist and physicist John Dalton. His tremendous efforts led to the evolution of modern atomic theory. He was the first person to record color blindness. He also carried out his research to explain the shortage of color perception.

Early Life:Dalton was born into a modest Quaker family in Cumberland, England around 5th September 1766. He got his early education from his father and his teacher, John Fletcher of the Quakers school at Eaglesfield, on whose retirement in 1778 he himself began teaching. He spent most of his life teaching and giving public lectures. After serving ten years at a Quaker boarding school in Kendal, in 1793 he took another teaching position in the rapidly increasing city of Manchester. There he taught math and natural philosophy at the New College until 1800, when he resigned due to worsening financial condition of the college. Afterwards he gave private tuitions for mathematics and natural philosophy.Contributions and Achievements:In 1794 John joined the Manchester Literary and Philosophical Society, which provided him with an exciting academic environment and laboratory services. After few weeks he presented his first paper on Extraordinary facts relating to the vision of colors before the society. In this paper he explained that the shortage in color perception was caused by discoloration of the liquid medium of the eyeball. He himself was a victim of color blindness and was the first one to discover the concept. As a result Daltonism became synonymous with color blindness.In 1803, he published his gas law which is now known as Daltons law. In this law he basically stated that the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of each individual component in a gas mixture.John Daltons Atomic theory has three principles that remain relatively unchanged. First, Elements are made of the smallest particles called atoms. Second, all atoms for a particular element are identical. Third, atoms of different elements can be told apart by their atomic weight. Fourth, atoms of different elements can combine in a chemical reaction to form chemical compounds in fixed ratios. Finally, atoms can not be created, destroyed, or divided as they are the smallest particles of matter. Even though some of its postulates were opposed by many scholars and scientists, Daltons Atomic Theory stills holds a lot of significance as it created a basis for current science.Death:Dalton died of a stroke on 27 July, 1844 and was buried in Manchester in Ardwick cemetery. () ,

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Dmitri Mendeleev revolutionized our understanding of the properties of atoms and created a table that probably embellishes every chemistry classroom in the world.Dmitri Mendeleev was born at Tobolsk, Siberia in 1834. He studied science at St. Petersburg and graduated in 1856. In 1863 Mendeleev was appointed to a professorship and in succeeded to the Chair in the University. The Russian chemist and science historian L.A. Tchugayev has characterized him as a chemist of genius, first-class physicist, a fruitful researcher in the fields of hydrodynamics, meteorology, geology, ? 19

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