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Saha, Meghnad (1893 –1956) was born in Seoratali, Bangladesh in 6th October, 1893. Hepassed M.Sc. from University of Calcutta in Applied Mathematics. He derived Lienard – Wiechert potential (retarded potential) in 1918, bored upon special theory of Relativity of Einstein in case of point change. He published the paper ‘On Radiation-Pressure and the Quentum theory’ in 1919 – by keen thinking on how the heavier element like Calcium present in the high altitude. He also published ‘the Stationary H and K lines of Calcium in Stellar Atmosphere’ – describes the concepts of collision frequency of hydrogen atom on the photon. By 1920, MeghnadSaha had established himself as one of the leading physicists of the time. His theory of high-temperature ionization of elements and its application to stellar atmospheres, as expressed by the Saha equation, is fundamental to modern astrophysics; subsequent development of his ideas has led to increased knowledge of the pressure and temperature distributions of stellar atmospheres. He took the initiation and established Saha Institute of Nuclear Physics in 1948. He was also initiated to start Nuclear Physics in Universities. M. Saha was the first Director of Indian Association for the Cultivation of Science till his death.

 
 

Sahni, Birbal (1891-1949) was apaleo-botanist who studied the fossils of the Indian subcontinent. He founded what is today the BirbalSahni Botanical Institute in Lucknow. BirbalSahni was born in 1891 and was educated at Lahore and graduated from Emmanuel College, Cambridge in 1914. He later was awarded the D.Sc. degree of London University in 1919. He returned to India and served as Professor of Botany at Banaras Hindu University, Varanasi and Punjab University for about a year. In 1921, he was appointed as the first Professor and Head of the Botany Department of the Lucknow University. The University of Cambridge recognized his researches by the award of the degree of Sc. D. in 1929. During the following years he not only continued his investigations but collected around him a group of devoted students from all parts of the country and built up a reputation for the University which soon became the first Center for botanical and palaeo-botanical investigations in India. His greatest contribution was the discovery of a new group of fossil gymnosperms which he called the "Pentoxyleae". Sahni studied fossil leaves of Ptilophyllum, stem of Bucklandia and flower of Williamsonia and concluded that they all belong to the same plant which he reconstructed and named as Williamsoniasewardiana.

 

He was elected a Fellow of the Royal Society of London (FRS) in 1936, the highest British scientific honor, awarded for the first time to an Indian botanist.